The story of the relationship between a man and his mother, the latter having been reincarnated as a 1928 Porter automobile.
Most sitcoms are based on preposterous themes/starts. That's probably why they are supposed to be humorous. They often work at the beginning; yet, many soon make a viewer want some answers.
Gilligan's Island...given the number of different outfits that 5 characters had one wonders why they packed so much for a "3 hour tour, a 3 hour tour". Had they been told by a qualified meteorologist that the weather would be "getting rough" and that they'd be stranded on an uncharted island?
A horse is a horse of course of course
And no one can talk to a horse of course.
That is of course unless the horse
Is the famous Mister Ed!
Sketch shows don't count. They're not sitcoms and have a greater amount of leeway where absurdist humor can just run wild without any restraints on logic, character or story structure.