You're talking about the literary construct of character motivation. There's more than just 'getting the girl'. If that was all there was to it, then the show would be a bland one-dimensional romantic comedy. It's not. It's a sci-fi comedy.
"Character motivation"--yes, thank you for articulating succinctly some of what I was trying to say.
But...and I was really struggling to make my meaning clear in my post...no, I'm not
just talking about romantic desire, though Fry's love for Leela is the most obvious example of what I'm getting at. I'm talking about yearning for the unknowable, the unattainable
. Like, Leela's desire to know where she came from, who her parents were, where she belongs. That provided some tension and suspense to the show.
This story was limited to just one episode. but I'm also thinking of Bender haranguing Bubble Gum Tate to let him be a Globetrotter, and he was rejected again and again.
I guess I'm talking about the "what if" and "if only" scenarios that can dominate a person's thoughts until it borders on obsession. Unrequited or unfulfilled love is just a prime example of that, but there's also examples like, a botched college career or screwing up a sweet job opportunity.
Eh, I don't know if these thoughts really warrants an entire thread.