When you go at least a week without shaving or combing your hair. You dress completely like Shit and look just out right awful. Then just before a big get together or meeting up with a girl you like, BAM!! You clean up real nice. The contrast from before and after makes you seem so much nicer.
John: Dude, you look like shit, You goin to that party lookin like that tonight?
Mike: Nah man, I'm goin for The BAM Effect