I'm pretty lucky, my current job/team are pretty ace and I really enjoy working with them. But from all the crappy jobs I had before :

- When people expect you to mind read.

- People who habitually don't read e-mails properly or at all. If it's once in a while it doesn't bother me at all, we're all busy and can miss things, but it's such a waste of time to have to keep repeating yourself when somebody else just can't be bothered to read.

- Putting stinky food in the microwave. Especially fish.