The Friendly Ghost

I hope that after I cross over, that if I come back, I come back as a friendly ghost. What's with all the angry ghosts? I see the movies and every haunted house has some pissed off spirit in it, wandering around scaring the bejimmenies out of children. What's with that? They're all so black hollowed eyed, creeping around in fuzzy light, moaning and so on.