I used to work with this one guy. He were together on a project once. We were both pretty senior designer by that point in time. I had a little more experience overall, but he'd been with the company (and telecom) a little longer. Anyhow, he was a very soft-spoken guy, never arrogant or anything. I didn't think I'd have any problems working with him. And yet, every design decision that we didn't exactly see eye to eye, somehow he would always argue about it, and usually get his way. At first I thought, he knows this stuff better than I do because he'd been in telecom a couple of years more than I, so unless it was something I really felt strongly about, what's the point of arguing. But by the end of the project I (privately) didn't think I could ever work with him again. We still remained friends, sort-of, but professionally, I just didn't need that. Every little thing -- important or fluff, matters of personal opinion and taste and the like -- it felt that he never, ever would let anything go someone else's way. But he was oh-so-friendly and polite about it. Quite unctuous, actually. I'm sure that there was not any single incident in which he acted inappropriately in any way. It was just over the course of several months he never, ever agreed, changed his mind or let it go.