LOST was a show of mysteries and unlike procedural and crime dramas, it didn’t have them all answered by the end of the episode—or the end of the series. This frustrated a lot of people, not me, because I’m weird like that, but a lot of people felt cheated or just dissatisfied.
That’s the problem of having a series where the driving force is the what ifs, the whys, the hows. People tune in because they get hooked on wanting to know the answers. But answering the questions gives them limits. People might say it’s an ass pull or worse, the dreaded Deus ex Machina. And you can’t go back without inducing a retcon, and come on. That’s even lazier than a Deus ex Machina. So answering means everyone is stuck with what’s given, but never knowing, whew. No worries there. Hence, creators of massive mystery shows will probably avoid answering anything, at least until the clamor gets loud enough, and then you get stuck with something like Twin Peaks.
This doesn’t mean you should avoid questions in your own works, my writerly friends. But I’d make sure the answers make sense, not just to you but to the reader. Otherwise, you’re stuck with an evil smoke monster that can turn into dead people.