I think greed and other such words are quite judgemental. Humans function in ways different than we usually judge each other. I don't think there's anything wrong in wanting, or being ambitious.
However when we call someone greedy, we might not see under the surface. That person might be acting out from an unresolved issue from their childhood where they never had enough and this is presenting itself as what the outside world sees as greed.
Sorry, just a rant :)