Does this just make you hopping mad!?

Some wannabe gang crap-head tagged a large area of Idaho Falls over the weekend with graffiti. I think what's frustrating is that it's so senseless. Most crimes have a purpose... you know, killing somebody, or getting something for nothing. Not that those reasons are good or right, but what's the purpose of spray painting people's houses, cars, fences, etc? I don't get it. Please, somebody, tell me the purpose of spray painting people's stuff.