A Beautiful Character
I've been rewatching Cheers on Netflix and was moved by a particular scene in the first episode of Season 4. "Diane" was telling "Sam" how sorry she was to hear that Coach had died. In fact, in real life, Nicholas Colasanto, the actor playing Coach, had recently died. He and Shelley Long had worked together on Cheers for the first three seasons. The expression of genuine sadness she showed during that scene made her beautiful face even more lovely.
There has been some snarky talk on these message boards about her career failure. But sometimes a good actor like Shelley Long, together with superb writing and a strong supporting cast can define, and be defined by, a character, in her case Diane Chambers. Kelsey Grammer experienced a similar "failure" with his portrayal of Frasier Crane. She may try playing other roles, but we simply can't, and don't want to, see her being anyone besides Diane.