How does one develop a thicker skin?

I am a complete softy. I work in an industry that is dog eat dog. Yet I try and bring old fashioned values like honesty, kindness and integrity to work. Yes, I know! Sounds mad. But I have been told that you have no friends in this industry, everyone is out to get everyone else. People lie, steal clients, set you up all sorts of things as a means to an end. My boss told me today that I am too caring and that the caring ones get left behind. (However I am doing well despite this!). I need to know how to get a thicker skin? I just care too much about people. For e.g. there is this piano player at our mall and he is poor and blind. He used to play in the middle of the mall. (And get tips). I saw they have moved him to the parking garage, and there he sits playing in the parking garage where no one can see him. I was heartbroken. Please help I need to get mean nasty and hard, as apparently this is the only way to survive in life??