Graffiti, crap
The legend Mrs Burns needs to iron her clothes, hastily sprayed on a canteen wall exterior, is surely a nominee for the crappest piece of graffiti ever.

Over to you, readers.
written by Ma*k *ildo*e, approved by Matt

Written on a toilet wall at school was the legend "Dai Cooney hates hard work". It was only some time later did we realise that he'd probably written it himself.
written by an*nymou* us*r, approved by Log