Gum popping and cracking. So rude and distracting. My experiences with it has been women in my office, so you're sitting pretty close to it all day.
The bass on stereos, especially of it's the neighbor's stereo on the other side of the wall. You ask them to please turn it down and they don't see the problem, but they hear the music with a beat, and all you hear is the beat shaking your wall.
I live in a townhouse complex, and the office building is down at the end of the parking lot where my building is. During the day there are empty spaces all over the lot close to the office, but I get home from work and for whatever reason I just cannot understand the office staff is parked in the spaces in front of my door. They don't leave for another half hour so I have to park somewhere else and move my car after they leave.