the show introduced a thousand mysteries and either didn't provide answers or the answers were disappointing. In the end the show became an incoherent mess. And the writers were the worst in that they encouraged the obsessive analysis and importance of the plot and mysteries then at the eleventh hour when they couldn't cone up with a way to pull together the plot points they threaded they pulled a bait and switch by saying the show was really about the characters. I watched it all the way through but at the end felt like I wasted my time in all the hours I invested watching and analyzing it. That's why I don't even bother with lostesque shows like game of thrones, invasion, revolution, zero hour, v, flash forward, the event, daybreak, vanished etc. They rely on gimmicks instead of good storytelling.
bsg and heroes come to mind as far as dragging stuff out.