For me personally, it's the Season 8 episode "Space Mutiny", which was also the first MST3K episode that I ever watched.

That bit with Mike bonking his head on one of the many railings Servo placed in the Satellite of Love and tumbling all the way down it while yelling before splashing into water sent me into an absolute laughing fit. I laughed for a good 10 minutes at that, I kept replaying that scene. It was pure comedic gold.

Manos: ✋

Final Sacrifice.

Tough question! I see people have already mentioned Space Mutiny and Manos. So I'll go with Werewolf.

They sleep nose to anus, like a coyote.

Probably Puma Man, but it’s hard to pick just one.

Space Mutiny is my favorite, but since OP already claimed it (now who will bring toys to the children!?) I'll go with my close second, Overdrawn at the Memory Bank. It's such trash and Raul Julia tears up every blessed scene he's in. He only dabbles in dopples but his love for the cinemas is easy to reciprocate.

Time Chasers for me (and like OP, it's partly because it was my first ever episode)

Lots of others though, not an easy choice!

Season 3 - "Gamera"

It's got everything you could want. Inexplicably awful children, space travel, a giant rocket powered turtle. My partner and I have been randomly shouting "Capsule!" at each other for many, many years because of that movie, confusing a great many family members in the process. Absolutely wonderful episode.

I'm very fond of Jack Frost. It's as corny and delightfully bizare as one could want from a Russian mythology movie made in 1965 USSR, and the riffs are obviously great.

The Touch of Satan always stuck with me.

I will also say it's hard to choose. I suppose it really depends on my mood or feelings at the time. However that being said, Pod People is the most memorable to me, followed extremely closely by Cavé Dwellers.

Mitchell

or was it Mittens 🤔

Tough question, because there are some great ones.

A recent favorite from the Netflix era has been “Cry Wilderness”. The movie was laughably bad in the first place, but that just made it great for the MST3k treatment.

So many great lines in there. Like the old man talking about how all the animals and nature are his family and friends and they voice the bird responding with “He’s not my friend. I’m not indigenous to this area. Please call the police.” That cracked me up so bad the first time I didn’t hear anything else for at least the next few minutes.

And also the running gag around terribly unsafe firearm handling: “BANG!”

That now goes through my head whenever a show just waves a gun around like an obvious prop instead of at least pretending it could be dangerous.

Hard to choose, they are all great in their own way.

I guess "The Deadly Mantis" because of the "little man in the boat" joke that has changed meaning in adulthood from when I saw it as a child. Eegah and Manos do stand as cornerstones, but Mantis has that one line that is burned into my association with the show and holds a special memory.

My all time favorite is Blood Waters of Dr. Z. It is unhinged from beginning to end in the best kind of way. The story is bonkers, the special effects and makeup are awful and the acting is worse but it's all so good.

And to all the people new to MST3K you get the obligatory Pod People recommendation.

Squirm.

Mister Beardsley!?

I’m torn between I Accuse My Parents and Hobgoblins, though I also put on Monster A Go-Go a lot (usually as background listening because NOTHING FUCKING HAPPENS IN THAT MOVIE, but when things do happen the riffs are top notch (plus its host segments are top notch and the short is easily in their top 5))