Frasier has so many "bottle episodes". It's my favorite type of episode and they nail it everytime. The Cafe Nervosa episode "are you happy?". Niles and Daphne during the blackout. This dinner party episode.
They are so good! It just relies almost entirely on good writing.
One of my favorites is the one where Frasier is pretending to be Jewish for Faye’s mother. The different threads in the episode culminate when Faye’s mother opens the door to the powder room and sees Niles dressed as Jesus with a Christmas tree crammed in there with him.