Has anyone else noticed this?

That Bam Margera loves to do pranks to other people and he laughs hysterically when they get hurt, but when someone does a prank to him he gets really mad? I mean people like Steve-O, WeeMan, Chris Pontius, Johnny Knoxville.. They laugh when people play pranks on them. Especially Steve-O. You know that if he's not laughing, he must be in some serious pain. But why does Bam act like that? Like hes invincible and no one can touch him or something?