BTW, props to blondebear for taking crap for his post, rightfully acknowledging its legitimacy, and moving on without ignoring other posters. Calmly. Politely. Rationally. Many others would have dug their heels in, gotten pissed at other posters, disappeared from the thread, or pulled a wide range of other inane bullshit. Kudos.
Seems to be a pattern here.
http://boards.straightdope.com/sdmb/showpost.php?p=9771955&postcount=159
Two days before this OP. Blondebear is provoked, again flips the bird, and again does it just as she is leaving and can’t be confronted with any consequences.
I usually don’t flip people off just because it doesn’t affect them much except to make them crankier and does about the same to me. I get a lot more satisfaction from being really nice.
Yesterday on my way home I was trying to pull onto the highway and merge into traffic. I was doing this from a straightforward ramp (Austin locals – the onramp just past the 360/183 intersection) onto a mildly busy highway. I was in the exit lane trying to merge into real traffic. Usually this is not a big deal, but there was a bright blue PT Cruiser pacing me and hanging out in my blind spot. I went faster, he went faster. I went slower, he went slower. I could see from my frequent over-the-shoulder glances that he was a rather smirking young man apparently doing his best to impress his laughing girlfriend. Haha, oh so funny, the cheap old battered Saturn is going to be forced off the road!
I finally just checked my rearview to make sure the road was clear behind me and him, mooshed the brakes hard enough to send him well in front of me, and swooped in behind him going about ten miles under the speed limit. The traffic was light enough that I was able to do this without getting in anyone’s way, but it was still a dangerous maneuver and one I do not enjoy. I was about 2-300 yards behind them when I got back into proper traffic, but I accelerated quickly and was just pulling up alongside them when they were finding their own exit.
Both of them looked at me rather anxiously when my car sidled alongside theirs.
I made kissyfaces and a little wave. 
They call him Flipper, Flipper…