This happened a few years ago.
It was during morning rush hour. I had just dropped DS off at school and was headed to work. I was going north on a major street (3 lanes each direction plus a left turn lane). I approached a traffic light, which was solid green for both north and southbound traffic - so you could make a left turn if there was a sufficient gap in traffic to do so. As I approached, intending to continue north through the intersection, I noticed a woman in the southbound left turn lane. She was waiting for her gap in traffic, but was slowly creeping forward - not just inching forward to be ready if a gap appeard, but slowly moving into traffic. I honestly thought she was planning to pull in front of me, so I slowed down while watching her. This infuriated her, and there was a lot of arm waving etc on her part as I continued on.
Here's the best part: I watched in my rearview mirror as she made a highly illegal (and dangerous) U turn in the middle of hte busy intersection. She then wove in and out of traffic to follow me. When I was stopped by a red light, she got out of my car and came up to mine, banging on my driver's side window and screaming. I just kept the door locked and windows up, and tried to read the company name on her ID badge (wasn't able to, unfortunately). Eventually the light turned green, other drivers began honking and yelling at me, and I took off.
This was really stupid on her part for a number of reasons, not least of which was that this happened in Phoenix, in a high crime neighborhood, where road rage shootings happen with some frequency. She's lucky she picked on me and not someone who was a) carrying a weapon and b) unstable enough to use it.