Right on cue, I just got a little taste of this in Albuquerque today. I'm accelerating up the entrance ramp to merge onto I-25. There is traffic, but nothing unusual. There is a car to my immediate left blocking me from merging, but he's going faster than me and I'm going to have plenty of room to merge behind him. Cool, easy. But just as my opportunity to merge opens up, the guy behind that guy intentionally speeds up to prevent me from merging in front of him. Pretty sure he did this as soon as I signalled, but I'm not 100% on that. For some reason, though, he really didn't want me on his interstate.
Anyway, I'm now out of road and I need to either get over or drive on the shoulder, so I just merge and admittedly cut the guy off, but he saw me, he saw me signal, I had waited for the first driver to pass, and this would have been a normal zipper merge had this guy not been a jerk. Plus my lane was ending in less than 100 feet. I really don't think I did anything wrong here.
The guy proceeded to lay on his horn, move into the next lane on the left (which was wide open the whole time), pass me, cut me off, and brake check me while flipping me off. My 78 year old dad is riding shotgun, so I just let it go. Eventually the guy went on with his day and I went on with mine, but I'm baffled as to why he did that.
Also, I'm driving a car with very out of state plates, which normally buys you some forbearance, but not this time! First time I've experienced this in probably 5 years minimum.