When I was a student, we were encouraged to have a 'thick skin' because attendings, residents, interns, nurses, social workers, MA's, PT's, and custodians all tended to lash out verbally at medical students. And it didn't really matter how good you were, or nice, or helpful. Eventually, someone would chew you out for no reason other than you are a convenient person to yell at. People have more scruples about kicking a cat.
I remember the times this happened to me. I was publicly humiliated by one attending at a conference for asking the drug rep a question. One surgeon threatened to make me do M&M, since this patient's imminent death was all my fault. One day I was assigned to eight patients in the morning, and I couldn't see them all before rounds, and the resident told me that I was lazy and useless, and should seriously consider dropping out of medical school. I strongly recall one attending who spent 20 minutes on rounds screaming at one intern until she broke down crying.
So when I graduated medical school, I promised myself that I would not perpetuate this horrible rite of passage. I would be nice. And that's such a noble thing to say to oneself, but in reality, I was just as bad. As a resident, I made no less than two interns cry, and there are a few students who likely went home and blogged about what a jerk I was after getting dressed down by me.
The problem for me is that I expect a lot out of people. I expect 100% all the time. That is the effort that I gave as a student and resident. That is the level I want. But my 100% is not the same as other people's. And it's not like I had to miss my daughter's soccer game or my wife's birthday.
When I finished residency, I promised myself that I would try to be more understanding. Being nice is tough. When you're pissed off, it's hard to turn that into nice. But as long as you're willing to listen and try to understand, even the most withering criticisms can at least be constructive.