case in point...

exhibit a: comparison drivers.

You know the ones, the ones who have no idea what a speedometer is for, so they sit in the lane next to me and drive at the exact same speed I drive, which is fine unless I want to get past them or if there's someone behind us trying to get though. If I try and drive ahead, they speed up. If I try and drop behind, they slow down. They're always sitting in the right hand lane and whistling dixie. Excuse me but you're driving a moving vehicle and your brain is where? Criminy.

exhibit b, and worse still, is when I'm that poor bastard trying to get through. Now, I'm no Ayrton Senna (no, of course I'm not because I'm not dead, ahem) but I do take umbridge at being forced to drive at your pace because you're an idiot and I'm not. God.