I think most would agree that any addiction is probably not a good thing. And I see this in people who are unknowingly addicted to losing. They are the people (not just in tennis) that the closer the game/match the tighter they get or the more mistake prone they become.
I play a lot of team sports too, including wallyball here in the colder months... and there are guys that you just know are gonna blow points as that particular game nears a result. We all make mistakes, sure, but some people seemed wired to fail.