Ratings

0 Very poor episode, usually with an absurd plot, complimented by risible dialogue and acting.
1 Episode is generally poor but has a few redeeming features.
2 Reasonably good episode with a few basic flaws.
3 All around good quality episode.
4 A good quality episode with some sparks of brilliance.
5 The best of the best.

Yellow text = Canon source Green text = Backstage source White text = DITL speculation