One place where there’s really not room for a two-for-one special would be at a stop sign. Just because I’m facing you and am taking a left turn in front of you doesn’t mean that two of you get to go at once, one after the other. Each driver needs to stop individually at the stop sign. No, just because the fellow in front of you stopped doesn’t mean that stop counts for you too because you’re right behind him and going straight, too. One at a time, please!