Such a sweet, hilarious episode of The Simpsons where every moment is hysterical. The main storyline is so perfect -- the idea of a female version of Homer, only attractive, working at the Powerplant too that tempts him into being disloyal to his wife. This battle Homer faces is so funny to watch and almost makes him look like the victim. The substory is great too. It all blends in together so well and is such a classic episode.
There are so many great eps, I haven't seen them in a long time.
Off the top of my head: X files cameo, Who shot Mr. Burns, the hot pepper, when lisa fails at babysitting bart and she knocks him unconscious, Lisa in the future, the one where Homer peed inside one of the twin towers, and there are probably more I'm forgetting.
You Only Move Twice (Hank Scorpio and Globex Corporation episode)
Homer Goes To College
$pringfield (Legalized gambling + Mr Burns casino episode)
Homer The Great (Stonecutters)
Marge Vs The Monorail
The Simpsons 138th Episode Spectacular
Homer's Barbershop Quartet
Homer Badman (Homer gets accused of sexual harassment)
Who Shot Mr Burns Part I + II
The Summer of 4 Ft 2 (4th of July vacation where Lisa makes new friends)
The Simpsons Spin-off Showcase
The Springfield Files (Mr Burns is the an alien)
Supercali...docious (Mary Poppins parody)
Just ones from the top of my head. Seasons 4-9 are the best TV comedy in history.
The one Michael Jackson was in
A Streetcar Named Marge
The Halloween iconic episodes
Stark Raving Dad.
That episode is inexplicably well written. It still surprises me that MJ during his untouchable uber-fame era was willing to be this MJ-parody figure. They were able to have a Michael Jackson episode without needing to have a MICHAEL JACKSON episode. This is the reason it's a fantastic episode, and doing the opposite makes it flop horribly (see: Lady Gaga episode. Don't @ me I'm a stan but it was horrible).