I've seen some dj's acting like stars, being arrogant to kidz and all..some even demanding from promoters to prevent kidz from coming close to them.. thats a BS if you ask me..

chatting before or after the set, asking autograph or taking photos is ok, like Mark wrote its the least dj can do for the fans, but on the other hand, sometimes some xtc head comes in and starts shaking the table with turntables, or comes into dj booth boring djs with his music wishes that often dont have anything in common with music being played, or jumps on him..
I remember even some falling over decks, messing with decks/mixer while dj is going throw his bag for a next record, spilling drinks all over record bag..and so on and on..

this kind of things I guess would make anyone nervous..