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.