1. Prius, most days. Bicyle, most days as well.
2. The "carbon footprint" of your car isn't zero. The energy you put into it comes from somewhere, and the energy to produce the vehicle wasn't inconsiderable, and the energy to dispose of it at the end of its life is quite non-null, too.
3. Your net costs would be lower if you got a cheap compact and paid full price for gas. I'm about due to trade in the Prius, and that's the way the math is adding up. But as you demonstrate so indelicately, the bragging rights can make up for the lack of any actual economic advantage.
4. You don't know your own modus operandi, much less anyone else's. Not so much for you with the telling other people what to do, huh.