Gypsy, I'd say it's probably more that if the foundation of your existence is the responsibility to feed and house your family and suddenly your ability to do that vanishes, then you are liable to become utterly irrational and react like a cornered animal. That would explain why the man in Speed's link killed his family first - to protect them from his inability to look after them. Twisted, yes, but it has an insane logic and is a form of behaviour that has been repeated numerous times.