Favorite 70s Sitcom

From Wikipedia-

A situation comedy, or sitcom, is a genre of comedy centered on a fixed set of characters who carry over from episode to episode. Sitcoms can be contrasted with sketch comedy, where a troupe may use new characters in each sketch, and stand-up comedy, where a comedian tells jokes and stories to an audience. Sitcoms originated in radio, but today are found mostly on television as one of its dominant narrative forms. This form can also include mockumentaries.

Which Sitcom that premiered between 1970-1979 would you call your favorite?

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