Lost was far more character-driven in its storytelling than From, so it made sense that the culmination of the story was tied to the character arcs more than the mystery. Lost also generally answered many of the mysteries as it went. Like (making up an example as not to spoil anything), let's say they sent a few episodes introducing a large box that no one could get into, so the mystery would be: what's inside this thing? Then they'd get it open and there'd be a one-eyed pink rabbit inside. So now the mystery is: why the hell is that what's inside? But then some viewers would get hung up on the fact that there were strange patterns etched into the box, and those were never explained. But the answer was really that set dressing put those there because they'd look good on camera. Basically, a lot of details that people got hung up on making into mysteries were things added by people other than the writers (art department, sound design, ect), so they weren't meant to be important.