Is batman insane?

I have never read the batman comics, or really watched the movies (Other than the Dark Knight) but after watching my friend play a batman video game (Arkham Asylum) I have decided he is insane. My friend is against this idea. (He read the comics as a kid)

In my opinion anyone who dresses up as a bat to fight crime is insane. Even the fact that he saves jokers life repeatedly when he knows doing this will get more innocent people killed seems to be a sign of insanity.

Opinions?