Strange thing, a young woman driver did this "deliberately slow down in from of you" thing to me a couple of weeks ago. I had done nothing at all to offend her, and never saw her before or since. But for three blocks she slowed down to about 5 mph, watching me in the rear view mirror all the time to see if I'd try to pass her in another lane, I guess.
Since she was in front of me, I just turned left on the street that I wanted, and she continued on, speeding up to normal speed as soon as I turned. I figured she was mad at her boyfriend or something else, nothing to do with me, but just looking for someone to annoy.
It's interesting how differently the different genders react to such things. I just thought "silly girl, grow up," but if I'd been a woman and it had been a guy deliberately slowing me down and then yelling at me, I can see why that would be cause for concern. And I didn't get her license number. Duane, your wife did better than I did.