I'm a lifeguard at a waterpark.
On Wednesday, I was dispatching our body slides. Basically I stand at the top and tell people when to slide down. Its a great, easy job.
Well, we weren't busy at all, so there were no lines most of the day. There was a group of annoying teenagers (about 7 of them) that refused to listen to the rules. They would slide down before I told them to, go down on their stomachs, etc.
So, after reiterating the rules to them for like the fourth time, I was done. I told them that if anyone broke the rules again, they wouldn't be allowed to go down the slide.
That seemed to work since they were listening to me now. However, they decided to get shit-eating-grins and ask me every 5 seconds "Can I go down yet?".
This annoyed me even more, so anytime they'd ask, I'd immediately dispatch the other slide. Then, I'd wait til the person on the other slide got to the splash pool, and then dispatch the shitheads. I only did this when he would ask "Can I go down yet?" with a stupid smirk on his face.
Eventually a couple of them caught on, but it was great when the stupid ones never picked up on it.

tl;dr Kids don't listen to lifeguards so I made them wait a looong time on the slides.