#3 reminded me of this. I had a boss who had a screaming fight with his ex-wife, on speakerphone with his door wide open. Everyone could hear. Really, just about any use of the speakerphone bugs me. It should be used very sparingly, but that was the most egregious example.

The other thing that bugs me are the overly social/unproductive people. I'm not crazy productive, but it still bugs me when people come by my desk all the time to chat. I often have to end the conversations by saying I really need to get back to work, and I don't want to be a jerk and refuse to talk to people. It just bugs me that they assume because they don't have anything to do (or that they're choosing not to work at that moment) that they assume I don't have anything to work on at that moment.