Why Are People Jerks?

Yesterday I was stuck in traffic on the freeway. Apparently a tanker full of propane had rolled at a major freeway interchange, and traffic was backed up on all freeways for miles as a result. In fact, the propane was leaking and local residents were being evacuated.

As I sat at a near standstill for an hour, I appreciated that all the hundreds of people on the road were being patient and courteous. Mostly. After a while I saw an old rusty truck drive up the right-hand shoulder, passing everyone. That made me mad. What makes him so much more important than the rest of us that he can't wait his turn too?

Five minutes later a BMW and a Lexus came zipping by on the shoulder. A semi saw them coming and pulled out into the shoulder to cut them off, forcing them to wait in line just like everyone else. I admit I internally began to cheer. The BMW driver started honking and swearing and acting like a complete idiot. I think it took him a minute to realize that the truck driver was doing it on purpose. At first he just seemed annoyed at the truck driver's obvious incompetence. Then as Mr. BMW realized that the truck driver was trying to prevent him from being a jerk, he became even more of a jerk.

As he gesticulated wildly and offensively, Mr. Lexus calmly rode further onto the shoulder, completely off the pavement and onto the dirt and grass (that dropped down at a 45 degree angle) and passed both the BMW and the semi. I found myself hoping that he'd get stuck in mud as he tried it. Alas, he made it around fine. Then Mr. BMW did the same thing, only he included more honking and rude gestures as he passed the truck.

So my question is, what gives people such a sense of entitlement that they permit themselves to act in such a fashion? Why is this acceptable behavior to them? It is arrogant, thoughtless, rude, mean-spirited, and selfish. What is WRONG with people? Why do we let them get away with it? I can't wait for Karma to make its rounds.