I'm going to stop at a blinking yellow traffic light and flip off another driver
Why are you going to flip off the driver?
He has been driving crazy
It's good to be concerned about a driver. But flipping off another driver is rude and often leads to a potentially dangerous situation, like road rage. Better to report the person to the police and give them his licence plate number.
I'm not going to rile him up that bad. Just waving at him is more than enough.
Still you never know how someone else will react. It could be really dangerous, keep your cool and ignore them.