"2. People passing you and then cutting over in front of you with less than two car lengths of clearance! Again, this happened to me at least 100 times"


My explanation:

1. The drivers doing the passing, woke up in the morning and decided:
a. They are the only person who should be on the road, and how dare anybody be in their lane, and require them to slightly turn their steering wheel slightly back and forth to pass them, and to show their utter hostility, they will pass them with the east amount of clearance possible, to make sure the passed know who is boss on the road.
or
b. How dare anyone on the road not drive at least the speed they are driving, irrespective of the passed vehicle's own safe speed or the speed limit, and they then cut them off to show how inadequate the passed drivers are.

Its all about, "its all about me, everybody else is wrong, case closed, I don't want to hear it" mindset.