Critiques in my painting class tend to be a two day affair. This is both because my class is large (16 students, and most produce anywhere from two to ten paintings between critiques) and because we all have a lot to say. For me, these things tend to go well. I know that it's my paintings, and not my worth as a human being, that is being evaluated. Besides, the other students and the teacher are there to help and therefore never cross the line into downright cruelty.
That being said, I heard something interesting while one classmate was taking their works down and another was setting up:
"Oh, I forgot. We're not supposed to tell them what we like."
...what? I mean, sure, you don't want crits in which all the feedback is 'you're amazing!' because that isn't really a crit. It's actually pretty frustrating and useless. But at the same time if all you're hearing is 'don't do this' and 'that looks strange' and 'you should reconsider', that can be dispiriting as well.
The thing about changing and innovating in your work is that sometimes things don't work out, but sometimes they do, and either way you have to go on from there. The positive part of a crit provides an anchor for future innovation. If you leave it out, you're stranding your studio mate.
So I guess what I'm saying is: other people are people too.