It's funny what we remember. When handing out scarves with different patterns, or cupcakes with different colors of frosting, I would hear my daughter's nursery school teachers admonish the children, "You get what you get, and you don't get upset."
I remind myself of this all the time. Sometimes, I can change, control, or choose; sometimes I can't -- in which case, it doesn't help to get upset about it.
This saying is a good example of the "fluency heuristic," by the way: we remember ideas better, and find them more valuable, when they're easy to remember -- for instance, because the words rhyme. (For some reason, I get a big kick out of this.)
Do you have any childhood sayings that have stuck with you? Rhyming or non-rhyming.