2. I'll take that small pothole head on rather than swerving to the middle of the road.
3. I'll stop talking with the person beside me and move over, without having to constantly be turning my head during the conversation to check for cars.
4. If the car stays behind me for a while (which I can check via the mirror) I'll give a thank-you wave before it finally makes the move to pass me.
5. I have been on roads where I will sometimes choose discretion over valor and the shoulder over the side of a road with a truck passing 2 feet beside me.
I find mirrors more useful on country roads. In the city, I would also just assume there is a car behind me.