why do people go out of their way to vandalize things?

why do people do all these things go out of their way to buy supplies spray paint and vandalize things? me and my neighbor used to drive to work together and we could not afford garage parking center city, the city was too big to walk though with more then a million people living center city and so we had to find street parking somewhere, the only places we found the car got spray painted and vandalized the police couldn't do anything about it because there is no security footage from any camera. its unfortunate that people vandalize other peoples things. its not like the person vandalizing gets anything out of it, he has to use money for spray paint.