SSN
What I don't get about Social Security Numbers is how insurance companies can get away with using it as your ID number. They tell us never to carry our SS card in our wallett, but you have to carry that medical insurance card, so the effect is the same. A few years ago, I tried to get my insurance company to issue me a new number that was not connected to my SSN. I tried in vain, and finally fired off a letter to the state office that oversees insurance. The next year my company changed insurance and happily they generated their own ID numbers.
-Steve G.