Have to imagine the state of television at the time. Just about all weekly shows were episodic. Each episode written as a single story that didn't connect to any others. If you wanted a serialized show you had to watch soap operas on one of the 3 or 4 networks that aired television. The high budget ones were on late at night. Falcon's Crest, Dynasty, Dallas, etc.

Twin Peaks was one of (if not the first) serialized genre shows with a mystery box element. Surreal imagery, a wide range of odd characters, and fantasy and horror elements. Nothing like it had been on TV before. It became huge and the "Who killed Laura Palmer?" mystery entered the zeitgeist and was as commonly talked about as Who Killed J.R.? around the watercooler.

Then season 2 comes around and the network tells Lynch he has to solve the mystery for the audience and reveal who killed Laura palmer and move on, something Lynch never intended to do. Unfortunately, there just wasn't anything to move onto. Once the mystery was solved the show was pretty much done. It limped along awhile and got a movie but David Lynch pretty much left and still talks about how he hated the second season

https://www.vanityfair.com/hollywood/2017/05/david-lynch-twin-peaks-season-two

The real legacy of the show is what it inspired. X-Files was heavily inspired by it, with Fox Mulder becoming the Agent Dale Cooper of the show, a "spooky" agent who investigated strange phenomena and mixes pseudoscience and mysticism into his investigative techniques and theories.

It also opened the way for more serialized genre shows like Buffy to tell longer story arcs. And other mystery box shows like LOST.

So most likely, by now, you've been ingesting a steady supply of what made Twin Peaks great at the time, but which has been refined, evolved and filtered into hundreds of various horror/sci-fi/fantasy serialized TV series.