As I said, I have a BFA. That means a large whopping percent of my college career was spent in art classes. And while the other disciplines in the school had critiques less often (maybe twice a week), for the graphic design program we were critiqued on our output every single class. If you took a basic full load of courses that meant being critiqued at least two times a day Monday through Friday (sometimes 3 or 4 times a day). We critiqued thought processes, thumbnails, proofs, comps and final art.
One thing you notice about college is that the people you end up with the the junior level of courses is much smaller than those in the freshman level of courses. In computer programming that was because of General Programming II and Calculus II. In graphic design we didn't have "weeder" courses. Every damn course weeded out those who didn't have what it took to go on.
You may think I'm being overly-dramatic there, but these critiques were not gentle things. Usually once a week was the "did you really mean to put so much suck into this?" critique. Now student to student we were pretty light. However the teacher always got their say. Most where rat-ass bastards too. Sure, they'd help you in class, give you all the help they could outside class, but when it came to critique time, they would open with both barrels.
Seem cruel? Obviously you've never been in a client meeting discussing design work. The only thing better for us would have been to include mind-reading courses.
So after four years of that type of crucible you develop a tough skin. Or you drop out. By the senior year of classes if you haven't developed the mental calluses to allow scorn and ridicule roll off your back you would probably need to see a psychiatrist to help with the cluelessness problems. In my "freshman" class we had about 300 students. I graduated with 24 in the winter (and I believe there were only 20 that spring). That's what's called attrition.
Some people have asked me why rejection doesn't bother me like it does other writers. This is why. Sure it bothers me, but I get over it quickly and move on. In my critique group sometimes I want to tell the person critiquing me, "You're holding back, damnit, tell me what you want to say!" Of course you can't do that in the Milford/Clarion style.
See, there's two different kinds of critiques. There's the professional kind which talks about the work (art or writing), it may or may not include suggestions ("I thought you were going here..." or "I think this could be stronger if you..."). Suggestions aren't necessary (although they do sped the learning process). This is the kind of critique that as a writer you should be seeking out. The kind that points out the flaws in the work, the things editors would toss your manuscript in the bounce file over. Of course, there are always differences of opinion (many of my later critiques with the Hamsters have extra notes on the hard copy that say, "so-and-so is correct pointing this out," or "so-and-so is completely off base with this comment"). In that case you look at if the majority agrees you messed up the imagery, you'll want to look at it. If the audience splits, or if only one person points something out, it's author's choice (which doesn't mean ignore it, it means evaluating the critique and seeing if a change would make the story stronger or if it would lose something). And all these critiques, even the ones you think are most cruel, are an attempt to help you and your work be better.
Then there's the other kind. The poisonous personal attack where the critiquer decides that it's mostly a character flaw of the author for any problems in the manuscript. Ignore these people. Find a better group of critiquers. A critique about a piece of work is never about the person.
I think I related the story of my worst critique a long time ago (and it's a post by itself). Nothing, I repeat, nothing an editor can say or do, nothing a fellow writer could say or do, could come close. The #10 has been set. Most others don't get past #6 in comparison. I am invested in my work, and if you tell me my baby is ugly I'll be upset. But it doesn't come close to the inferno that was that critique (short story, it changed my life). Tell me that you don't want to publish my piece. Eh. I've had clients tell me to my face my work sucked and they weren't going to continue working with me/pay for it. Just giving me a rejection or telling me that this simile doesn't work for you isn't even close. This far down the road, there's only one person that could get close to affecting me that deeply. And it's not anybody in my critique group or any editor I submit to.
Unfortunately I don't have much advice on how to get to where I'm at. It involves walking through Hell. Once you do that a little flame doesn't bother you. And if necessary, you know you can do it again.