Why do people keep getting at me?

Every time I do something that could have been done better, people take something away from me.  I even end up finding good things in it each time, which makes me feel tricked.  Still, it changes things and makes me uncomfortable.  I don't feel I was even beckoned to be as critical.  Some things just aren't full-blown the deed, and I go back and rethink what I thought that should have been different.  Things all happen for reasons, though, but I just have to learn from what happens and try not to do anything bad in the first place...