Looking to enact some petty revenge? Find a missing cat or dog poster with a cash reward, take a good photo of the pet on the missing poster. Create a new poster with the pic you took that reads something like:

Missing Cat. Not my cat but I am highly interested. Cash reward

Make the cash reward 2, 3 or 10 times more than the original missing poster's cash reward. Add the phone number of the person you seek revenge against. Then hang up the poster next to the original missing cat posters.

Rest easy knowing your enemy is getting calls telling them what a piece of shit they are.