Is there anything?S

Is there anything you can do that's legal for brake checkers? I got brake checked heading back from my weekend plans on a quite 2 lane highway in Wyoming (I was doing 70 in a 65, he was doing...68?) I came up behind him and was preparing to pass when he jams it down to 40...no reason. I pass him later; late teens or early 20's, skinny, stupid hat and what I'm assuming is is overweight GF in the passenger seat both flipping us off. Just me, my wife, and my 2 sleeping girls, just trying to drive home. I wasn't tailing him, i wasn't doing anything to threaten him...

Yeah, people like that make me....Furious. Frankly Its not a stretch to imagine how people get so upset they do something stupid like shoot other people or run them off the road over road rage incidents. I think the reason it makes us so made its because there is nothing we can do...i mean, is there? Basically you are helpless, subject to their whims because short of ending up on the nightly news, what can you do? Its this impotence that gets me (us?) wound up more than the act.

Oh you flipped me off...well...SCREW YOU!

Anyone have ideas of ways to mitigate the impotent rage? I try and just let it go, but its hard (HA! hard and impotent in the same sentence)