Don't settle for mediocrity; never let good enough be good enough.
The old grey donkey, Eeyore stood by himself in a thistly corner of the Forest, his front feet well apart, his head on one side, and thought about things. Sometimes he thought sadly to himself, "Why?" and sometimes he thought, "Wherefore?" and sometimes he thought, "Inasmuch as which?" and sometimes he didn't quite know what he was thinking about.