I don't look down on the dude for living in a cave - as long as he keeps himself clean and doesn't steal... but why not also have a job?
I can't imagine how quickly my bank account would go up if i worked 9-5 and went home to a cave.
My girlfriend is a waster. She grew up in a family of wasters. Sometimes i see veggies in a plastic bag in the garbage - so i take them out, wash them, chop them up and serve them for dinner only to hear compliments on it
If i saw someone idling their SUV while eating dinner, I would go and tell them under the guise that i'm looking out for them. "excuse me everybody, someone has left their SUV idling"... no guilt trip, no offense. If they then told me "i'm keeping it cool for when my fat ass is done gorging on half of this meal" i'd tell them they are a prick and be on my way.