So I was out walking the dog just now when a guy rolls down the window of his parked car and tosses out a half-full [half-empty?
] styrofoam cup of coffee. There was no garbage can nearby - he was clearly littering with wild abandon.
I picked up the coffee cup and....
I know what I wish I had done. I wish I had placed it underneath one of his windshield wipers in such a way that the coffee spilled onto his windshield.
I'm interested to hear anyone else's stories of Instant Karma or Spontaneous Retribution.

I picked up the coffee cup and....
Spoiler :
...showed it to him, as if I thought he might have been mistaken and he had simply dropped it. When he made the 'It's OK' hands, I placed the cup on the roof of his car.
I know what I wish I had done. I wish I had placed it underneath one of his windshield wipers in such a way that the coffee spilled onto his windshield.
I'm interested to hear anyone else's stories of Instant Karma or Spontaneous Retribution.