My guess is that if "Twin Peaks" had continued into the 1990s, they might have brought Josie back for guest appearances (via doorknob)...but it still would have been really weird and ambiguous with no story-based explanation.

Agreed on both Matt and Libby, obviously.

"Melrose Place" was on its last legs in Season 7, and I think it was largely the writers wanting to "bring Matt back" without actually paying Doug Savant for a character portrayal. It was so stupid. But "Melrose Place" Season 7 felt like a totally different show, altogether.

With Libby, her character was just so mysterious and intriguing that her intro-followed-by-sudden-death all within the same season ended up being a big wasteful tease. Fans really wanted to learn more about her...but they didn't even give us that, when she came back as a guest star in later seasons.

Same with Season 6 of "24" -- it was indeed a convoluted mess. The storylines throughout the entire season felt contrived (even beyond Curtis's suicide mission). Rena Sofer felt really out-of-place, as did the sudden introduction of Jack's criminal insta-family. Bringing back Milo only to kill him off halfway through the season was pointless. Kal Penn was totally unbelievable portraying a terrorist.

"Sliders," however, is one of those so-bad-it's-good shows, for me. No matter how campy the Season 3 episodes got, or how wooden Jerry O'Connell's acting was throughout Season 4, I can watch almost any episode (even the bad ones) with fond nostalgia.