#1: Making as if I'm "challenge accepted" to the pick-up truck who's been egging me on, now beside me at a red light ... only to take off really, really gently as the Lumbering 4x4 With Huge Wheels races away. The icing is if I get beside that person at the next red light with a huge smile on my face; it's pure smiling eye-contact as I pull up alongside, very, very slowly (line-of-sight angles permitting).
#2: Driving like a sane human, and getting tail-gated / passed by mini-vans. Makes me smile every time.
#3: Knowing I could pull away, hard, if I wanted. LOL.
P.S. For #1, why's there never a cop around when you need one to witness such things?