in one of their episodes.

Many years ago, I had an idea for a short story about an ambassador from a planet with a very long lifespan who lives on a planet where a generation is a matter of days or weeks. It was based on the idea of relative lifespans, as in the case of a type of moth whose complete life is only a day. To the inhabitants of the planet, the ambassador would be considered immortal. After a short time, I believe the ambassador would tend to withdraw within himself. Isolated from his home by long transit times, he'd be unwilling to develop friendships with the locals because they die so quickly.