ScreenRant listed the 10 worst “answers” of LOST:
10. The Whispers are Souls.
The whispers come from the souls of dead people who haven't "moved on" yet like Michael.
It was an answer that gave evidence to the early purgatory theorists, which the show runner continually deny.
9. Desmond had Mind Powers because of Electromagnetism
Desmond’s powers were nonsense and caused "electromagnetism" stemming from the hatch implosion makes no sense because there were others near the Hatch who were not affected.
8. The Sideways Timeline is Purgatory
The opening of Season 6 seemed to suggest that Juliet had split the timeline.
In one branch, the island remained and nothing changed. In the other branch, the island was destroyed and the events of LOST never occurred. But then we found out that it was not a branching timeline, but purgatory. It caused a lot of confusion — "they were dead the whole time!" — but even those who weren't confused were left bitterly disappointed and upset with the reveal. Even some tried to salvage the sideways branch as being some sort of “dream” state (before moving on?) but it all comes down to Bad Filler episodes.
7. Walt’s Special Powers
Walt plays an important role throughout the first season, and to some extent, the second season as well. It's very clear that he has some type of special connection with the island, and has some sort of mental powers. He also showed some sort of teleportation powers in Season 2, as he appears to Shannon right before she dies. But a growth spurt exiled Walt from the series and the disappointing answer for his mysterious powers was that he was "special.”
6. Revived Locke was Actually the Man in Black
Locke dies midway through Season 5, but we were briefly led to believe that he was revived after returning to the island. Of course, Locke remained dead, and the Man in Black was simply using his corpse to have a corporeal form to split the Others from Jacob so he could try to escape the Island. Of course, a paralyzed Locke crash landing on the island can walk, run and hunt like an Outback warrior, but his remains stay dead without resurrection even though Jack’s dad wanders around it at will?
5. The Confusing Numbers
The numbers were another major mystery, and they were a part of LOST from the very beginning. In the end, we found out that the numbers correlated to Jacob's numbering system for the candidates to replace him. Why would an island god need to be replaced by a mortal? As if that wasn't lame enough, it also doesn't answer anything else: Why were they broadcasting from the tower? Why do they bring people bad luck? Why are they seemingly cursed? Why do they constantly recur both on and off the island?
4. The Smoke Monster’s origins
There were countless theories regarding the Smoke Monster, and it remained one of the most prevalent questions throughout all six years of the show. And then we found out it was just the result of some magical reaction after Jacob’s brother (the Man in Black) fell in the magical glowing light cave.
3. Jacob and The Man in Black
For that matter, Jacob and the Man in Black remain extremely divisive and controversial figures. "Jacob" was mentioned as far back as Season 3, and while there are various "hints" of their existence throughout the first couple seasons, most people found their existence a total blindside that ruined the show. The show pivoted abruptly to a supernatural fantasy show with no reason. All the mysteries, questions and Easter eggs were washed away by two god-boys playing with humans (spirits) as pawns. There origin story episode was very good but it should have been shown early in Season 1 if that is the true mythology of the show’s creators (which most people believe was not - - - because they wrote themselves into too many dead ends to rationally explain.)
2. Magic Island
Perhaps the biggest question of all contained the most disappointing answer of all. "What is the island?" It's a question that permeated LOST throughout all six seasons, as it was clearly evident that it wasn't just a regular island. There were scientific facts thrown at us to analyze, research and theorize. From an alien ship, to a parallel universe time portal to a secret military base, there were viable alternatives to the explanation that the island was just “magical.”
1. The Magic Light
But why was the island magical? The explanation was that the island containing some sort of “magical light” that does magical things and keeps evil at bay from doing what exactly? What is the magic light exactly? Was the magic light the cause for all the crazy island stuff? Locke's sudden ability to walk? Smoke Monster's origins? The ability for the island to literally move through space and time?. Electromagnetic properties of the island? The ability to disappear? Magic as being the answer to all the unanswered questions is a cop-out of epic proportions.