Dumb Behaviour

The only way I'm going to get this terrible incident out of my head is to put it down in words.
Breanne and I were walking back to the house from Rite Aid yesterday- she was picking out some graduation cards for her cousins. I'd been feeling sick the last couple of days, sleeping a lot and not eating much, so I went with her to get some fresh air. As we're strolling down the sidewalk, a truck speeds by and someone in the vehicle screams out the window at us in what I assume is an attempt to scare. Being in a bad mood, I flipped the truck off. The driver slammed on his brakes, turned around in a driveway and came flying back towards us. The truck, teal green, screeches to a stop in the middle of the lane going the other way and the driver gets out of the truck.
It's a guy with a buzz cut, roughly my age, glasses, in full army fatigues and steel toed boots. In the street, the camouflage suit does the opposite that it's intended to, making him very visible and clownish looking. His name tag says Thompson. He instantly challenges me to a fight.
He is clearly worked up and gets right in my face, hoping I take the bait and retaliate.
I explain to him why I flipped him off and that I considered what he did a rude thing to do. In his defense, he claims "it's a free country." I think that's just about the stupidest thing I've ever heard, and I hadn't heard it since elementary school. I argued that obviously I wouldn't have flipped him off if he hadn't screamed out the window at us.
"It was my brother who screamed, not me," he says.
"Well why are you the one out here threatening me then?"
"My brother could kick your ass too."
It was at this moment that I recognized him. About three months ago, we were both hired on the same day to work at Interstate Brands in Biddeford. We sat through a two hour orientation together, and I recall talking with him for a while. I remember him being mousy and polite. And at that moment, I'm certain it's him.
I tell him I know him. That we had orientation together at Interstate Brands.
He starts to stutter and says, "I've been gone the last month."
I tell him it was about three months ago. Then I ask him what his name is.
He sheepishly tells me it's Shawn.
He pretended not to remember me and starts heading back to his truck. He can't resist throwing a parting shot and yells, "I'd kick your ass but I don't want to go to jail."
Still suffering from my fight/flight adrenaline, I say, "Then why did you get out of the truck?" Breanne pulls my arm and says let's go and so I start walking back to the house.
Shawn and his brother, and a girl sandwiched between them in the truck cab, whiz by us, revving the engine, going at least 50 past the 25 speed limit sign. They didn't scream this time and I didn't flip them off.

The conversation was longer than that. I'm sure I've forgotten a few things he said and a few things I said. I wasn't as calm as I made myself out to be, but I was more practical than the ape in the army pants was. The problem with this whole encounter though isn't that there are stupid people like Shawn out there, dressing up in his fighting suit and tooling around looking for a confrontation. I was the problem.
I encouraged Shawn by flipping him off. I didn't have to do that. I certainly shouldn't have done it with Breanne at my side. Shawn could have been some maniac that was actually looking for a fist fight, and not just some sorry soldier trying to look tough in front of his little brother. Perhaps if I hadn't recognized him he wouldn't have gotten uncomfortable and walked away. Any number of things could have happened.
The point is, I feel embarrassed for my behaviour. I should be wiser than that, and though it's a cliche, I'm really too old for that sort of thing. Everyone gets worked up and overexcited sometimes, but I feel ashamed that Breanne had to see me arguing with some loser, looking just as stupid as he did.