Work Ethic in Theatre

Now I'm a bit crazy when it comes to work ethic. I'll work myself beyond the point of exhaustion and usually end up injured or sprained and whatnot. What I don't understand are the people who literally don't care. We have an intern here at OST who has had writ problems since the 2nd week she got here and has done nothing but complain and try to get the company to pay for her medical bills. When she got onto my service as my assistant, I knew her acting routine going in. I showed no sympathy, but was kind and clear in stating that this was her contract and this is what was expected of her. She has continually disappointed me and continually complained. She is now being let go by the end of the week and we are in the process of training her replacement, another intern, and instead of being grateful(it's her desire to go home), she is being a bigger bitch and making it more difficult to let things go nicely and one good terms. I am trying my best to understand her but she doesn't want to do theatre for a living, so why did she take this job from someone else who does? I know once me and Kelly get into our respective "grooves" things will be great, I just wish I had found a better way to work with this girl for future reference, for I am bound to run into this situation again.