I just discovered two people I can barely stand at work...
That one who feels the need to butt in to stuff that doesn't concern them and act like a know-it-all. For instance, you're speaking with a client and your neighbor over the cubicle wall starts addressing YOUR client's situation, not even knowing the full story, and giving a bunch of erroneous info. Glad I dwell in an office now.
The other one is the one who takes my time and theirs to come to my office and talk about something they don't understand, but yet want to argue with me when I explain it. Why in the world did you come ask me if you already know better? You could've left me alone to do my work, I would've been totally fine with that.
Jerks.