Re: I thought that episode was original, until...
What matters, what makes them fresh and original, is how those ideas are put together and expressed.
I don't read as much sci-fi as when I was younger. "Concept" stories seemed the norm back then, while much of the recent stuff I've encountered feels like soap opera—where maintaining the series and the characters is the primary concern. I'll often shy away from anything pitched as "part of the popular X series!"
Maybe I've seen all the basic concepts now, or maybe the genre (meaning publishing and fans, etc) has actually changed. Or maybe some of both. "There is nothing new under the suns of Kalgash."
"No, I better not look. I just might be in there."
—Foghorn Leghorn, Little Boy Boo