A self-righteous person thinks their beliefs and morals are better than everyone else's. If you're quite sure the charity of others pales in comparison with yours, you might be self-righteous.
Join the Old English words self, meaning "one's own person," and rightwise, meaning "virtuous," and you've got somebody who thinks very highly of their own morality. A self-righteous person thinks they can do no wrong, and goes about with a "holier-than-thou" attitude, judging and scrutinizing everyone else. A fur designer may view PETA activists as self-righteous when they picket his fashion show. You may consider a friend self-righteous when it comes to musical taste.