I was attending a small liberal arts college in the early '70s and I had a car, one of the few. People asked me for many rides. I said yes and the realized I hated doing it. Then I replaced "yes" with "I'll think about it," a polite way of saying no without saying no.

A friend called me on it : "Aren't you really saying no?" "Yes". So some of the time I said "no" and some of the time I said, "I'll think about it."