I remember seeing this as a kid thinking this guy was a complete psycho who just did this for no reason because they never fully explain the context. Once you actually find out how this guy's life was unfairly ruined by the city, you start to understand his rage.Marvin definitely let the intrusive thoughts win. But after hearing his story I not only sympathize, I completely understand. Every man has his limit, and we as a society have pushing people's limits past their breaking point.