Why do we care?

I'll just throw out a question I've wondered about for a long time: Why do we care what strangers think? You may, at first thought, say that you don't, but have you ever had a bumper sticker on your car? Have you ever had a political sign on your lawn? Sometimes I've seen bumper stickers that make me laugh. For instance, "Jesus loves you. Everyone else thinks you're an asshole." I can understand that. Someone had a notion to make people smile. That's nice. But what about something like, "My child is an honor student at Phineas Fartwaffle Junior High." Do you really care whether some stranger driving behind you knows personal information about your kid? How about putting a political sign on your lawn? "Vote for Donald Doomsday for President?" In this highly divided political climate, do you really think a lawn sign is going to change anyone's voting choice. And....do we really care what some stranger going by thinks of our political thoughts? Don't know if anyone reads these blogs but I've just started writing again after a few years absence, and I'd really like to see a thought or two in response to my ramblings.