How come white people can't say ******?

It doesn't bother me when someone calls me "White boy" or "Cracker". how come when i go to some of my friends and say "what's up *****" they get offended...i thought that is ok to say. it must be a dubble standard for black people. Oh, and another thing that pisses my off about black people is,when they think something is funny but it isn't(Dave Chaple, house of pane, etc.).