Unfortunately the world is full of losers like this. It was probably due to the fact that you were in a Supra, as I doubt that they would of noticed you if you were in a Mondeo. Its just the nature of owning / driving a nice car. For the most part you will get positive reactions to your car, but you will always get random idiots notice you and do something like this.
I remember when I left my brother in laws house once, and was driving slowly down this small street in my CRX. When suddenly for no reason whatsoever, a 6'5" meat head jumped in front of my car waiving a monkey wrench, whilst shouting all kinds of crap at me. I have no idea who he was as I had just helped the brother in law move into a house, in a totally different town to me and so hadn't come across this guy before.
Just put it down to them being loser's
Mark