Ah, I see, so you are the great all-knowing Oz who can discern a motorists deepest and darkest motives.
Whether or not the OP derived pleasure from the tailgater’s discomfort upon being slowed down does NOT = his driving actions were jerkish. Were his personal feelings jerkish? IMO? No, in yours, you obviously are hell-bent on believing that the OP’s sole purpose was to “punish and impede” the tailgater.
Since you seem to be a bit slow on the uptake, let’s break it down for you carefully and step by step.
The OP’s driving actions were quite appropriate under the circumstances.
The OP had ALREADY been doing close to the speed limit. Given the tailgaters behaviour (blaring horn, brights, driving inches off of the OP’s bumper, remember that part?), it’s highly doubtful that he’d have behaved any differently than he did had the OP been driving the BREAKneck speed of 35 instead of 30.
As it is, the OP gave VERY clear signals and opportunities to change the situation to the tailgater, upon whom the responsibility for behaviour modicification rested during this incident.
Not only did the OP give a very CLEAR signal to the tailgater, he gave a signal that is appropriate, safe and recommended by law enforcement as per info that has been provided for you in links in this thread by other posters.
The very clear signal was tapping his brakes and slowing down. This says “either pass, or back off”.
At this point, the tailgater has three choices, he can do as the front driver requests, or he can continue his dangerous behaviour. He chose to continue badgering and harrassing the OP.
Did the OP slam on his brakes in the hopes of getting a huge settlement? No. Did he flip off the tailgater and give him “COME ON, let’s go” signals? NO.
He again gave a clear, safe, recommended and EASILY recognized signal, by again tapping his brakes and slowing a little more.
That second signal was “Pass or BACK OFF”. The tailgater again refused his options and continued his bad behaviour.
At which point the OP gave his final signal, he slowed to 15mph, the signal he gave was “This is PLENTY slow for you to pass, OR you can back off and I’ll go back up to the speed limit, but I’ll NOT be intimidated by your actions”.
Apparently you’re the only one who translates “I’m standing my ground against this bully” into “jerkish behaviour”.
It’s obviously not YOUR opinion, you’ve made that quite clear, but IMHO, not even his thinking “haha” in the back of his mind makes him a jerk. Merely human, as most people likely think when confronted by a bully and standing their ground.
And again, whether or not the OP was a jerk “back” to the tailgater or not, his actions were phenomenally stupid and ineffecient. Not only did he get himself even FURTHER wound up by trying and failing to bully someone, he didn’t get that which he was trying to accomplish either, that of getting to go however fast he wanted to.
So all his fussing and raging was for nothing. The thing is, and the thing you keep missing, is that all his fussing and raging would have been for nothing no matter what!
Even if the OP HAD decided to go back up to 35, so what? The tailgater would not have been able to pass, STILL, certainly less so than at 15mph, and he’d have continued his assault on the OP either way.