Another things that grind my gears: Idiot coworkers...
Got two of them on my shift alone. One is a rather obnoxious narcissist who thinks he's the greatest thing since sliced bread, but refuses to do much in the way of his job, even going out of his way to avoid it. In fact, if the weather is nice out, then he "conveniently" calls in sick, in order to go biking in the mountains, and even lies about it to our boss, forcing my boss, more than a few times, to have someone else cover the shift. It really eats into the department's overtime budget. He also insists on hijacking conversations to be all about himself, what he's done outside of work, and has a very thin skin. Any time someone doesn't listen to him, doesn't want to talk to him, or gives him a good flick on the nose, this easily bruises his massive ego. He even threatens union action for any policy he doesn't like, or isn't implemented fast enough for his liking, and likes to take meal breaks twice as long as are allowed.
The other one can't find his own ass with both hands and a map. He's worked for our department for over 2.5 years, yet he still has no idea what our number even is, and has to ask us for help on what to do on even for the simplest IT tickets. He was legitimately upset that I got the coveted Sunday - Thursday shift over him, but our supervisor said in no uncertain terms, he didn't want to babysit this guy, and wanted someone who knew what the heck they were doing. This guy refuses to buy or use cell phones, and frequently goes out "in the weeds" for hours on end to tinker on things over doing his job. He even asked our division chief, whether he he can get credit for doing things like jailbreaking a PS3, installing a new software on his personal home router, and other personal projects on work time. You can guess what the division chief's answer was.