So which TOS episode had the best teaser ? I find that an easy one. I remember in the early 1970s, being very young and new to Trek settling down to watch an episode of Trek only to be royally P.O.'d when it was not on and in its place was some sort of military show. I still remember the goose bumps that I felt when I saw that the "UFO" being pursued was the Enterprise flying through the clouds.