Being in a really boring lesson at school, or walking anywhere (yeah that works for me)
English is a personal favourite, can't stand poetry >.<
Other than that it's the fact that certain things can be done quickly, and others take time. I currently have an idea for making a singleplayer adventure out of WoW, using Mangos to emulate (not that I know if its possible yet though, I've only just got a personal server up and running for myself)