That's not true at all. I don't believe people are naturally good, I believe they are naturally assholes. Being nice to them is just the most reliable way I've found to avoid bringing out those inner assholes.
Madness string 21324
Fire extinguishers filled with paint have been used for graffiti, usually tagging, for some time. I've used it once, and it was lots of fun but very hard to control and you get covered in the paint yourself.