I've seen all the above, too many dozens of times to count.
How & why people don't use common sense or any understanding of physics when driving tells me 2 things:
Either they're too stupid to be allowed to operate a vehicle...
Or, they really think they're the only person who matters.
The concept of Courtesy is sadly lacking in many of life's activities, but in a vehicle, it's particularly bad.

I can recall 40 years ago driving in dense 65-70 MPH traffic on I-5, I-10, etc in L.A., everyone a few feet apart, and actually driving with awareness.
Those days seem to be gone; I can't count how many times I've had to pull off an immediate-reaction evasive move.
For the last 15-20 years, I've tried to avoid having another vehicle near me.
And for that matter, there are like 2 people who I'm comfortable with if they drive...both racers, with more talent than I have...