1. The Mythology
Without a doubt, I think what made The X-Files such an everlasting series is the mythology it created. It has a very complex storyline which is very compelling when started from the very beginning. Multiple viewings have offered new glimpses and hints that I otherwise did not catch on my first viewing, allowing things to make more sense as they take on new meaning. The X-Files was a drastically different show for the 90s with a very deep serialized plot. No one ever really expected a sci-fi show to have such a rich story filled with aliens and government conspiracies. It remains one of the reasons the show is remembered so much today because of how compelling they made it. Some plot points may have faltered toward the end or have been prolonged for too long which perhaps hindered some fans enjoyment of the final seasons, but overall the mythology broke new ground for the television industry. As I said when discussing the influence X-Files has had on the television industry, we never would have gotten many of the great dramas of the past decade without X-Files. It not only pushed the envelope, but elevated what both a science fiction and drama show can accomplish.