I'm a middle of the road kind of driver. Almost an equal number of people pass me (sometimes at crazy speeds) as I pass myself. My dad is a slow and steady type (and also feels superior about it), so I get to hear all his "stories" about how so and so passed him and sped up fast but hit every light just like he did, but he wasted less gas (or some other reasoning). However, he conveniently doesn't note the likely five other times in the same scenario where the guy hit every light and left my dad in the dust.

Personally, I notice people I pass a lot because of my dad's comments, and am very self conscious of when I pass somebody but get nowhere. However, most of the time, I passed that person because they were just driving too slow (I'll not slow down and go 5 mph under the speed limit just to make some random person happy), and even if they are going the speed limit, if they drive inconsistently (hit the brakes, slow down/speed up randomly, etc), I just want to be away from them and somewhere safer/less stressful to drive.

I use cruise control a LOT, so I'm annoyed at having to hit my brakes for no reason other than some stranger's whim.

Sometimes we aren't jockeying for position, we are just getting away from somebody.