Cheers

Ted Danson, Rhea Perlman and George Wendt are the only actors to appear in every episode.

Including the spin-off 'Frasier', Kelsey Grammer played the character of Frasier Crane for 20 consecutive years.

After Ted Danson announced that he was leaving the series, NBC wanted to continue the series by having Woody take over the bar. But Woody Harrelson refused to continue with the series without Danson.