When I used to dj at a local bar I had a few belters causing me trouble, one night a guy kept touching the record deliberately and trying to scratch. I shouted at him this wasn't a cool way to behave, then he tried to place a pint of lager on the revolving record, so I grabbed him, luckily security quickly arrived and ejected him before I had to kick his sorry ass!
Another time a guy threw some lit matches at me because I denied his request to play Duran Duran!
And another night I was in a bad mood as people kept squeezing past and bumping the decks all night, finally after the 20th or so polite request when a girl did this I shouted at her, she was shocked and was almost crying- she said to me it wasn't her fault she was so fat!
I actually felt bad about this last incident, although it was funny as fuck.