But stopping to beat him up would lower your Tank, wouldn't it? Never brake or suddenly slow if you don't have to...
And running him over with the car would ruin your Aero, so that's out-the same applies to giving him a piece of your mind, which would involve opening the windows. That means shooting him is out too...
You could gesture back at him I suppose-but your windows are probably tinted too dark for him to see you properly. Saves on AC though...
The power lost from using your horn to express your defiance would be fairly undetectable though, so I guess that's your best solution.
...and the above is how you know you're an Ecomodder!