badgering purchaser rant!
When people see a really nice or old car, they want to know what it is worth, not that they want to buy it, but like "how much do you make?", sometimes asking how much you'd sell it for is just their way of looking for a number to pin on it. Other people are looking for a bargain. If someone is seriously interested in buying your car for a fair price, they will be more careful, badgering you or asking dumb questions will just make you mad and drive the price up, which doesn't really matter if they have no intention of buying in the first place. It can be flattering and annoying all at once.