I'm very near the end of Cheers, and it really is a fantastic sitcom. A little cliche, but a lot of the cliches are cliches that the show invented. The whole idea of a recurring on-again, off-again relationship between two characters is called a "Sam and Diane" relationship to this day.
Shelley Long leaving the show, while a blow at the time, was the best thing that ever happened to this show, as it forced them to change the dynamic, which kept the show from losing its touch. I don't think any other show that lasted 11 years was more deserving of lasting 11 years, because it was constantly changing, which allowed it to stay fresh over that whole span.
10/10