One day my husband was walking down the street on his lunch break when he saw a some members of a street gang standing on a corner. He walked over to the gangstas, introduced himself, and said, "You know, we try to help the community as much as possible." He mentioned several ways their families might have benefited from what the people where he worked did and continued, "You're making our job a lot harder by painting graffiti on the walls. Would you please stop?"
For the rest of the years he worked at that facility there was never any more graffiti from that gang - or any other.