I have read this book called Love First and part of it talks about detaching. Basically it says that detachment is good, but you should detach with love. It is normal to feel angry, mad, etc. But I don't think its healthy to take out that anger on someone else - even if they are the ones who incite that anger.
I faced this same predicament when I first started teaching. My first class was 8th grade history, and the kids were completely nuts. They had already been through a revolving door of teachers and scared all of them away. At first I was too nice. I quickly learned that being nice wasn't working however, and I went to the other extreme, being mean.
The trick, I think, is to detach while at the same time being loving. It can be hard and it is a constant balance but it can be reached.