cat, or is he being a jerk because he wants something from me?

Case in point: earlier this morning I was sitting at my home computer, and he starts shoving his face against my elbow (he's a tall cat). He walks away and then he suddenly comes over to chomp down on my arm. Naturally, I look over, and the water bowl is empty. Okay, cat you are thirsty, but did you really have to bite me? Why can't you just scratch at your bowl when you want something like the dog does? Is it because you are an asshole? Yeah, that's it.