What buggs you most about your co-workers?

[ZTAngel]

I'm bumping this because one of my co-workers keeps pissing me off.
I have all the marketing supplies in my office. Pens, coffee cups, brochures, etc. are in my office. When someone needs a pen or something to give to a client, they'll stand in my doorway and say, "Hey ZTAngel, I need a pen to give to Mr. Jones. Can I grab one?" Sure, no problem. Well, I have this one asshole co-worker who just walks on into my office. I'll be doing work or I'll be on the phone with a client and he'll walk on in without saying a word. He'll go through my office, grab what he needs, mess up the organization of everything (throwing the pens around until he gets the color he needs or dropping stuff all over the floor), not clean up his mess and then walk on out without saying a word. I got so annoyed today because he did this several times that I finally just now sneered at him, "Sure...help yourself." He just looked at me and then kept doing his thing. Ugh.