Clueless has nothing to do with it.
I was in the left lane, about to pbutt some butthole in a Baby Ruth truck, when at the last moment he not only whipped out into the lane in front of me but he FLIPPED ME OFF in his left side mirror. I had to brake hard enough for the ABS to kick in.
Another time on that same road trip I saw a group of 3 trucks that appeared to be playing "leapfrog" - as I hung back and watched, they took turns micro-pbutting each other. Strangely, when no cars were coming, they were perfectly content to stay in the right lane, but as soon as a car tries to pbutt, suddenly the last Trucker in line decides it's time to pbutt the other two. And yet NONE of the three ever left the pack - they just took turns pbutting each other for the entire time I watched.
And then there was the pair of butthole Truckers who drove side-by-side for a good 20 miles, forming a multi-mile backup behind them. If I'd had a CB radio in my car, I'm sure I would have heard something like "Hyuk Hyuk! Lookie at that long line of 4-wheelers, Clem! They's backed up all the way to Too-Sonn!"
I think bored Truckers do this kind of poo just for the fun of it.
That's EXACTLY how they rationalize it. Truckers are on a tight schedule, they need to make their next delivery on time, Truckers are driving for WORK while 4-wheeler drivers are on VACATION, blah blah blah.
Don't worry - as fuel prices get higher, things will get better as these "professionals" get driven out of the business and all those goods start being shipped across the country by rail.