A guy who was just minding his own business on his scooter in Thailand witnessed a bunch of purse snatchers trying to grab the bag of a passing woman. A swift sidekick followed, followed by a bunch of swift punches to the face. Because when you snatch what isn't yours, the long fist of justice follows.
Most of the time vigilante justice is neither swift nor just, and it's usually just plain stupid. But isn't it nice when it just works?