At one point in the mid-1980s and even into the early 1990s, NBC's Cheers was the biggest and most popular show on television. For 11 seasons and 275 episodes (including three double-length episodes and a triple-length finale!), Cheers was a phenomenon on the same level as Seinfeld and Friends. Unlike those wildly popular television series, however, about halfway through Cheers' lifespan, the entire game changed.

The first few years of Cheers were defined by one central relationship: that of its co-leads, Ted Danson and Shelley Long, who played Sam and Diane, respectively. Their will-they-won't-they romantic tension kept audiences coming back for more every week, right up until Shelley Long decided to say goodbye to the one place where everyone knew her name.

Related Ted Danson Apologizes to Cheers Co-Star Kelsey Grammer for Decades-Long Feud

Cheers actor Ted Danson regrets his long-time issue with co-star Kelsey Grammer, directly apologizing to Frasier's leading man.