The one annoying co-worker

JN msgs me: "Why does he always think he's part of every conversation?"
Truth.... I don't presume to try and understand the creepy inner-workings of our requisite annoying co-worker's twisty little mind. There's always got to be one, and R is the epitome of all that is annoying and creepy in a co-worker...
If it were just that he butts into every conversation, we could possibly live peacefully in our environment. However, I do not make it a common practice to listen to the constant advice of a know-it-all who two days ago I watched systematically pick little specs of stuff (L asks: Was it crumbs from lunch? Or the crusties he's always picking off his head?) off his sweater and.... eat them. I kid you not. And while I would theoretically like to be the one who bravely takes the moral high-ground.... frankly, the moral high-ground is WAY up there, and I'm afraid of heights. Once in a while, the urge to divulge all the grossness I feel towards this person wins out, and I have to have a minor ranting session with JN over msn. I know, I know... "He who is without sin casts the first stone." But it's not like we're outwardly pelting the guy with verbal missiles. Just privately, among ourselves, over the internet, while he's sitting in the room. Yes, I am stroking the guilty conscience. On the upside, my ability to keep a straight face has reached new and uncharted territories. :)