I read 'The Lottery' the other day, and I really loved it. One thing Pat Wood did that rang true for me was to describe how devestating the effects of criticism were on her hero, Perry. The effects of harsh criticism on a child are devestating. And the opposite it true also - praise and encouragement bring out the best in them. (In everyone.)
Writing is the same.
I was a member of several critique groups, and the advice was 'No negative feedback - only constructive feedback!' That is essential. Not negative - constructive.
I know that many writers hesitate to send their work out because they are afraid of rejection. But that's only part of it. They're also afraid of criticism. Don't be afraid. The only way to learn is to send your work out and have it looked at by people who have no emotional connection to you or your work. An honest critique group can be amazingly helpful. If you're a new writer who is afraid to join a critique group, remember this. We all started this way: palms sweaty, heart pounding, brand new manuscript clutched in our hands - terrified that the book will be ripped apart. A good critique group will not rip anything. If it's a good group, the criticsm will be contructive and help you learn. Your writing will get stronger, and you will feel more secure about it.
But a bad group can do harm. If you feel your group is too harsh, don't hesitate to change.
So if you are a member of a critique group, remember to temper your criticism. Try to find out if the person you're critiquing has a lot of experience or not. New writers are more sensitive. (Believe me, the first time I was critiqued, it nearly destroyed me. I felt flayed. Horrified. It HURT! ) Imagine telling the mother of a new baby that her baby is ugly. Well, that's how it is at first.
After a while, the skin gets thicker, and it's easier to deal with citiques. But in the beginning, remember how much it hurts, and critique accordingly.