> If I walked past litter on the ground in my home-town, I wouldn't say "Hey, not my job." and walk past it, I would pick it up for the betterment of my town.

This is this and that is that. Litter won't stab you, whereas I've had a friend get stabbed by a mentally ill person who asked for their restaurant leftovers, and were given them, only to then do just that. (Which is a bit different than what the OP is talking about, but you mentioned mental illness in society in general, so it seems fair to bring it up.)