J.J. Abrams does not make mediocre television. He and his teams set out to explore the biggest of life's themes--truth, reality, love and death--and his shows are admirable for their ambition and their failure.
ALIAS was a show about a woman who joined the CIA. It was gripping through its first two seasons, introduced some scene-chewing villains and then got a bit weird.
LOST was a show about a group of plane crash survivors on a tropical island. It was tense and exciting through many seasons, also introduced memorable villains and then got a bit weird.
But FRINGE started out weird--X-Files weird--and that's been its greatest strength. All of the themes the other two shows explored, but didn't always seem to fit within their initial premises, were able to live comfortably within the FRINGE universe. And, surprisingly, while it had memorable villains, they weren't as crucial to the show's appeal.
On FRINGE, anything, literally anything, was possible. If a herd of unicorns show up in tonight's series finale, I'll be surprised, but not put off by it. FRINGE was incredibly consistent throughout its first three seasons, started wandering in season four and took an interesting turn in this finale season. The different directions were partially due to a lack of network support (it has to be tough writing ambitious plots when your show could be canceled at any moment) and it would have been interesting to see where the show could have gone had it had a full season to explore its universe just a little bit more. So while I'm not recommending that you check out the thrilling two-part finale this evening, I do think it's a show worth watching some time in the future.