I wish I had some of the photos I've bombed that were taken by random people.
My favorite thing to do is give the bird to a person taking pictures of a crowd I happen to be in. For instance, like at movie premieres when someone takes a photo of the line of people. If I see someone taking a photo, I'll flip 'em the bird so that when they download them to their computer for editing and can see them full size, they find little old me making their photo much more awesome and memorable.