The Happy Days spinoff Mork & Mindy is remembered today as the show that made Robin Williams a household name — but despite the presence of one of the great comedic talents of the era, it didn’t remain a hit. The sitcom premiered to big numbers but sank lower and lower in the ratings until ABC called it a day after four seasons — cancelling a planned fifth season that would have focused on time travel. “I found out the show was canceled by reading it in Variety,” Williams told People in 2009. “In Hollywood, that’s like reading your own obituary: ‘You’re dead, good luck!’”

But by that point, Mork & Mindy — in which Williams’ alien character meets and falls for the Pam Dawber’s human Mindy — wasn’t the same show the actor had signed up for.