But to be honest, I think I see the situation differently, because where I am from we are probably a bit more relaxed with words like that. Of course we know it's not a nice word, but I think that we use the words more freely than people in the US probably do.
For exmple, saying the F-word regularly is very common her where I am from, but I remember when I went to New York my teacher who was original from New York told us NOT to use the f-word, and be very careful, because people would get mad.
Idk if it's completely true since the f-word is used a lot in movies, but that's what he said

Well, if she didn't want to be called a beep she should not had been acting like a beep
But I agree with the OT, that for Ted calling her that was also a stressed out decision. And because he was hurt as well.

I think Ted using that word was also a stressed out decision and he was just trying to make his best friend felt better. He meant it at the time but not later after she came back.

She angry with him, because calling someone the C-Word is a step too far for anyone. It was selfish of her to just up and leave, but I can sort of understand it, because she was freaking out - it wasn't right for her to do what she did, but it was more of a stressed out decision than a completely selfish one, even though it was selfish.

Yeah, he was. And I agree with him. And I thought Lily was overreacting - but I guess she was kinda ashamed of what she'd done, and didn't like being confronted with it? And that's why she got so angry with Ted, instead of just understanding the situation he was in back then.