My X-Files time ended at the end of season 5. And it's the same with my DVD boxset. I wanted to watch all the seasons but when I reached season 6 I got bored again
Regarding LOST: Maybe it was my luck that I started to watch it around the time of the final season. Because I did not want to spoil it for me I did not discuss anything with other fans or read interviews. But after I finished the show I read a lot of background info and I am still amazed about the love for details. It has this huge mythology behind it that I appreciate a lot.
[ spoiler warning! ]
I am still surprised some people believe the island was purgatory, even after the ending. The only purgatory storyline were the "flackbacks" in season 6, but this is just a very small part of the whole mythology and they are not even connected much to the rest of it. The show would have worked without them, so the cheesy ending did not bother me much.
And I really liked the over the top time travel storylines... but I guess that's just my personal love for things like this
. I can understand why people who loved the first season got lost during the strange ways this show decided to take.