Do you know someone who always lets you pick up the tab with the proviso, "The next one's on me," and it never is? Meet the non-alternator. These cheapskates are banking on the likelihood that you won't be so socially uncouth as to make a scene the next time it's their turn. Even if you should be so bold, be prepared for any number of excuses why they can't pick this one up but promise to get it, you got it, next time.