I'm sure it's not completely any one person's fault, just as I'm sure it wasn't a full-blown rivalry. Nobody says you have to be best friends with your coworkers, and a TV cast is no different. But Teri being at the center of conflict, whether or not it was her fault, has been documented from the start of the show. There was the overblown Vanity Fair photo shoot story, where after a season of Teri being placed (sometimes literally) front and center, the other women reacted negatively. After that, for Season 2, every cast photo had 5 versions, with each woman getting her chance to be in the middle. If you google promo images from that season, you'll see it's true. And it was very intentional.
Teri reportedly angered Eva Longoria when she signed autographs at her wedding to Tony Parker, whereas the other actresses waved to fans but didn't interact. Teri also negotiated her contract and salary separately from the other female leads, who opted to negotiate together. Eva called Teri a "lone wolf" in an interview toward the end of the show, and Nicollette Sheridan said she was the meanest woman she knew in some of her court documents. When the show wrapped, Marcia, Felicity, Eva, and Vanessa went in on a group gift for the crew; for one reason or the other, Teri wasn't included. Teri published that letter in which she basically said she would never disclose what happened between her and the other women.
Make with any of that which you will, but there was obviously some tension. Whether there was truly ill feelings or if it was just a simple case of people not being each other's cup of tea, we might not ever know. But I don't think this had an any bearing on her performance.

Not really sure of the full story. It could be that Terry was very unpleasant.
It could also be that the other women of the cast resented her being the lead in a sense, so naturally bonded over that and made her an outsider.

I don't think she was a bitch. A lot of other actors who have worked with Teri in the past including Dean Cain have only had good things to say about Teri in interviews and it was Marc Cherry (The Show's Director) who was said to be the one who was difficult to work with and Nicollette Sheridan claimed he abused and assaulted her on set and other cast members spoke of similar abuse.

It don't matter if it's raining
Nothing can phase me
I make my own sunshine
And if you think you can break me
Baby, you're crazy
I make my own sunshine

There is no doubt that Teri was placed front and center in the marketing for this show at the beginning. There's a Season 1 poster that literally has Teri front and center, with the other women standing behind a hedge. Not only was Teri the most recognizable at the time, but Susan was supposed to be the emotional anchor of the show. I imagine tensions arose from that. After all, nobody really denied altogether those Vanity Fair rumors.
I'm also now just remembering that I once met the photographer who did the promo work for the last season (and possibly a few others before), and he said that Teri had to be photographed separately from the other women. I imagine the same thing happened with that Entertainment Weekly cover from 2012. The other three women are holding hands or linking arms, and Teri looks like she was photoshopped in after the fact.

I love that Hatcher can do material that has you laughing out loud at the situations she's put through, do physical comedy and also completely nail emotional scenes where she has to cry her eyes out.
In your opinion she does this, but to some she's not that great of an actress at times. As I stated she had a lot of effort in her acting the first 6 seasons of Desperate Housewives, but I feel she gave up during the last two seasons. Doesn't make either of our statements correct. It's just how we perceive things though.
Also, Felicity was a Golden Globe nominee for Sports Night before DH, so she wasn't completely unknown.
I've never heard of Sports Night. I saw online it only lasted two seasons so I guess it wasn't that big of a hit when it started like Desperate Housewives was in the beginning.

The only good thing about American Crime is Felicity!!!!!

At the time Teri was 'a media darling' and had a strong following.
I remember Teri being more of a sex icon of the 90's. Teri posed for a lot of provocative pictures. I feel she used her looks more than her acting to get herself known. Do an image search for Lois & Clark and that picture from the 90's that made her extremely famous of appearing naked wrapped up in Superman's cape still comes up to this day.
Probably the one cast member that surprised everyone was how strong Felicity Huffman was, which is why she won an Emmy in 2005.
She earned that reward. Rewatching Desperate Housewives, I am amazed at how well she performs in her scenes. She really did become a breakout star of Desperate Housewives since she was unheard of before the show. I don't really care for American Crime, but I'm glad she's still acting.

The difference between Teri and Marcia is that Teri was the co-star of Lois & Clark, while Marcia was the 10th billed actor in an ensemble cast. At the time Teri was 'a media darling' and had a strong following. So when they cast Desperate Housewives, she had name appeal. She had the name appeal to draw viewers that probably never gave Melrose Place the time of day. When I started watching DH I had never heard of Marcia Cross.
But what was very apparent from the start is that Desperate Housewives was an ensemble cast and if anything, all of them were equally strong in their own right. Probably the one cast member that surprised everyone was how strong Felicity Huffman was, which is why she won an Emmy in 2005.

I think this is just it and what usually causes tensions on these shows - Desperate Housewives were more or less initially marketed as the Teri Hatcher show because she was the only one who had headlined a long-running show before, which for sure left some of the other ladies feeling sour.
Teri wasn't the only actress who had a show before Desperate Housewives. Marcia was pretty big in the 90's with Melrose Place. During Desperate Housewives run, Marcia stated in an interview she still had people come up to her to check for the infamous scar Marcia's character on Melrose Place had. I still think Marcia will always be remembered more for Melrose Place than any other work, including Desperate Housewives. Her character blew up Melrose Place which is something almost every fan of that show remembers when looking back on it. Plus Marcia was given opportunity to act more on Melrose Place than Desperate Housewives. Look at some of the crazy things her character did. Marcia pulled it off perfectly. She proved she's extremely talented at being a psycho.
Also I wouldn't consider 4 years a long running show if you're referring to Lois & Clark for Teri. The show is lucky it made syndication on TNT for a while because normally a show has to reach 100 episodes to enter syndication. I consider anything past 6 years to be a long running show.

I must have totally ignored the media telling me she was supposed to be the star of the show. I always saw the core 4 as equal leads (though we all have our personal favorite).

As much as I admire the 4 leads equally as actors, it is possibly they weren't happy with Hatcher's first billing, higher salary and being placed at the forefront of the majority of publicity images. Her unofficial star-or-the-show status (she was the star in season 1 though) was bound to irritate the women who had the same amount of screen time and work to do on the show.
I think this is just it and what usually causes tensions on these shows - Desperate Housewives were more or less initially marketed as the Teri Hatcher show because she was the only one who had headlined a long-running show before, which for sure left some of the other ladies feeling sour. I'm sure it wasn't entirely one-sided but it does feel like the other ladies isolated her; even today we occassionally see pictures of Felicity, Marcia and Eva meeting up, but seemingly never with Teri.
Similarly, Charmed was initially promoted as The Shannen Doherty Show and an unknown actress was cast as Phoebe before she dropped out and Alyssa Milano came in.

You reminded me of what Shannen did on Charmed when she was fighting with Alyssa. Shannen's last two episodes had her isolated from Alyssa to the point where Shannen's character was a dog in one of the episodes. They got creative finding ways to keep peace. I never would have thought about that with Susan's scenes where she's away from the girls. That's a good point you brought up though and now I wonder if that's why. She did have a lot of small storylines in the last two seasons that didn't involve the other housewives now that I think about it.
Shannen was also isolated from the rest of the cast during her last season on 90210. Albeit it was to a lesser degree, but they wrote storylines for her character that alienated her from the friend group.
And yeah, I would also say that having Susan live off Wisteria Lane for Season 7 could have also been an attempt to separate the women. Obviously, it seems like the actresses were professional and committed to the show, and I don't think the writers were writing around these tensions per se. But maybe they wanted to have a housewife move off the lane and they thought, why not Susan to get Teri away from the other women?

Yes, I was referring to her own history of being molested as a child. She spoke out at her uncle's trial where he was sentenced to prison. Her real life story is completely different than how her character handled a murder of a child molester.
What I did notice, however, is that in the later seasons, it seemed like Susan was largely isolated from the other women and would generally have more solo scenes whereas the other women interacted more. That, to me, was a good indication the rumors of the women not getting along with her had a little truth to them.
You reminded me of what Shannen did on Charmed when she was fighting with Alyssa. Shannen's last two episodes had her isolated from Alyssa to the point where Shannen's character was a dog in one of the episodes. They got creative finding ways to keep peace. I never would have thought about that with Susan's scenes where she's away from the girls. That's a good point you brought up though and now I wonder if that's why. She did have a lot of small storylines in the last two seasons that didn't involve the other housewives now that I think about it.

What happened to her uncle?]
I believe the poster is referring to the fact that Teri's uncle sexually abused her in her childhood (and at least one other girl), and how Susan's character deals with that material in Season 8. I personally don't think that would have affected her acting, at least not for the worst. I'm sure she was supportive of the storyline; they wouldn't have done it if she were that uncomfortable with doing the work.
Granted, I haven't watched the last two seasons since they aired, but I don't recall noticing a particular decline/change in her acting. Overall, I felt that the acting suffered as a result of middling writing, but nobody stuck out to me as seeming distant. What I did notice, however, is that in the later seasons, it seemed like Susan was largely isolated from the other women and would generally have more solo scenes whereas the other women interacted more. That, to me, was a good indication the rumors of the women not getting along with her had a little truth to them.

What happened to her uncle?

Teri's acting was completely different in seasons 7 and 8 compared to seasons 1 - 6. Seasons 1 thru 6 Teri put a lot of effort and life into her scenes. She was very enjoyable during her comedy scenes. Once season 7 started it was slowly drifting to where in season 8, she just looked bored in her scenes. There was a dramatic change in Teri's acting in season 8. I don't know if it was the type of storyline they were doing because of what happened with her uncle, but she does not look or act the same like she did the first 6 years of the show.

She was just a stick staring into space during her scenes. There was very little acting from her.
I don't see it that way, I enjoyed her throughout the seasons. But you are entirely welcome to feel that way.

Kind of ruined Susan for me.
The lousy writing for Susan is what ruined her character for me. Out of all the housewives, she had the most least interesting stories in the show. It's funny Teri's first billed in the credits because the other three actresses carried the show with their stories IMO. All Susan really had in this show was her relationship problems with men, mainly Mike. I don't know if Teri could ever pull off the acting the other three actresses did with their stories. I'm wondering if that could have been a reason Teri was never given much. Marcia pulled off her alcoholism storyline perfectly. Felicity did awesome with the cancer storyline and carried the horrible season that 5 was. Eva was awesome with her character's story of being molested as a child. Plus you can tell in the last couple of seasons Teri didn't like being on Desperate Housewives anymore. Her acting in season 8 was awful. She was just a stick staring into space during her scenes. There was very little acting from her.

Of course, I agree, and I've always been able to separate the fictional char from the actor/tress. For example, as I mentioned in my OP, I've never thought of Marissa in OC as a b*tch even though Mischa is considered to be one.
So what I meant in this case is that it kind of shined through Susan. Teri didn't do a good acting job to make me able to separate it as I can in other situaions.

That is unfortunate if you are so easily influenced by rumors you can't enjoy a character. Lots of actors are truly questionable people (instead of just here where it's possibly true but maybe not) but you should be able to separate the two and enjoy a fictional character without the baggage of the person portraying them.

Consider the daffodil. And while you're doing that I'll be over here looking through your stuff.

I don't say that I believe it's true. I'm saying that they still made some impact on me even though I don't want them to.

Why do you believe it's true?