James Branch Cabell

While it is well enough to leave footprints on the sands of time, it is even more important to make sure they point in a commendable direction.

The optimist sees a light at the end of the tunnel, the realist sees a train entering the tunnel, the pessimist sees a train speeding at him, hell for leather, and the machinist sees three idiots sitting on the rail track. "The optimist proclaims that we live in the best of all possible worlds; the pessimist fears this is true."