Mine is people going crowd surfing in poor clothing choices, with boots and anything dangling being particular hates. If I had a quid for the number of times I've been kicked in the back of the head by someone wearing steel toecaps I'd not be rich but I could probably buy a couple of pints of terrible lager, which brings me onto...

Terrible booze sponsorship deals. I detest Tuborg. And carlsberg. Stop making them the only available beers.