I have too many to list, but here's a good one.
Wife and I were talking about the high energy bill one winter morning.
I put the kids in my truck to take them to school. This was one morning when I didn't warm up my truck before leaving. Being young kids, they didn't understand that the heat in a vehicle comes from friction and the burning fuel in the engine, and that when it is cold it takes a few minutes to warm up.
So my oldest daughter, Allison, asked "Why don't we have the heat on?"
Lexie jumped in and replied "Because daddy doesn't want to pay a big heat bill."