Well the sow revolves around all of them. Debra included, but many people hate her with a burning passion, despite the fact she is in 95% of the episodes. She missed a bit of season 3.
But doesn't mean other elements of the show can't be enjoyable. A main character is just 1. There can be other characters or elements people enjoy, even if it's not the main one.

If you're gonna pretend to cut her hair, at least put some scissors in your hand!

He's the MAIN CHARACTER, the show revolves around himif you hate him so much, why do you watch it then??

Recovering Pessimist
The Ride Along
The Article
Big Shots
Cousin Gerard
Robert's Rodeo
Italy Part 1
Italy Part 2
The Author
Super Bowl
Say Uncle
Mother's Day
Somebody Hates Raymond
Angry Sex
PT & A

The Italy episode is when Ray really annoyed me. He complained the whole time.

Practically every time he opens his mouth and talks. Second only to his mother.

Ray's most annoying habits were his spin. The way he put the blame on Debra (The Checkbook) so he wouldn't look like an idiot. The story he put out about how he came to buying Deb, To Kill A Mocking Bird. Wow! Pure Raymond.
SkiesAreBlue

All episodes are chocked full of Raymond being annoying

I think Ray was at one of his worst moments when his book got rejected at the same time the family got the news that Robert made lieutenant. He slammed his hand on the table and walked off without saying a word to his brother. The rest of the family was only slightly better since they toned down their congratulations to Robert to not make Ray feel bad.

Everyone mentioned some good ones. I think his worst was in season 8, or 9. I forget which
Debra makes a harmless bet with the kids about whether, or not, he'd notice her new hairstyle. When Ray finds out, he acts like a child and accuses Debra of turning his kids against him, then saying it's Marie's fault that he thinks badly of Frank.
But it falls into categories others mention. He doesn't want to be a hands-on father, but wants the kids to automatically adore him. So if his kids think he's a joke, it's someone else's fault.
But overall, Majority of the characters are dysfunctional, and thus frequently annoying. So not like it's only Ray. lol 1 episode Ray may be the main annoyance, but in another episode, it may be Robert. And so on.

If you're gonna pretend to cut her hair, at least put some scissors in your hand!

Ray's most annoying moments this should be a fertile category. Most of the ones where I found him the most annoying are when he thought he was right and would get that big, childish smirk on his face. Then of course, there were the ones when he was acting like manchild. There were also the ones when he would try to act happy, or interested in the children and would come off as totally phony:

• The one when he didn't want to wait for a delivery person, so he got his mommy to do it for him. And when Deborah came home, he insisted that she was lying about having a doctor's appointment in the first place.
• Insisting that he was going to take the kids to the zoo, just because he was jealous that they liked to spend time with Robert.
• The whole trip to Italy, including his sudden attitude adjustment.
• Big shots, as someone else already stated.
• The times when he pointed out that he was the wage earner. (Especially in "The Sigh.")
• Every time he'd whine about having to do anything with the kids.
  I know I've left several out. But still, I do like that Ray Romano was willing to play his character as such a manchild wuss. I also like actors whose egos aren't so huge that they're willing to make total jerks out of their characters. (Another great is Bryan Cranston as Hal from Malcolm in the Middle.)

I just thought of another one, which I had forgotten since I've deliberately avoided re-watching this particular episode for years: Ray giving $1,000 to his high school buddies' terrible business idea without consulting Debra first in "Net Worth."

I will have to check out Big Shots again since I don't remember that episode well.
The Ray and Peggie dynamic was written very inconsistently by the writers.
In Cookies, they are archenemies. Robert: "Oh, you have an archenemy now, what are you a superhero now?" Frank: "Captain Big Nose."
However, in Sleepover at Peggy's, they seem to come to a truce. Then in Party Dress, they have a falling out again, and, finally, in A Date for Peter, they are back to archenemies.

Yeah, Ray's behavior in "The Garage Sale" was weird. Given the premise of the episode, I would understand his attitude if he had problems throwing things away (I can definitely relate to that!), but wanting another child came out of the blue.
I didn't mind his behavior in "The Wallpaper" because that whole episode was intended to be over-the-top for comedic effect.
IMO, the two instances in which Ray really went out of line were "Big Shots" (ruining the 1969 Mets experience for Robert) and "A Date for Peter" (trying to prevent Peter and Peggy from becoming a couple). I'm usually passive towards Ray's behavior for the sake of comedy, but his behavior in those two episodes was much more irritating than funny.

I respectfully choose not to contribute to this one, as I feel that I have done enough Ray Barone-bashing on this site in the last two years or so to last a lifetime. But remember, like Phil Rosenthal said: Debra was always so mean to Ray BECAUSE HE HAD EARNED IT.
Thank you for your time.