What's the monster in the jungle?
How did Locke get in the wheelchair?
Who conned Sawyers dad?
Who’s Jacob and how did he get to the Island?
How did the Black Rock get in the middle of the island?
Who built the hatch?
Where did the polar bears come from?
Who's Richard, how did he get to the island and why doesn’t he age.
How was Locke able to walk again?
How was Rose's cancer cured?
Who are the others?
What happened to the tail section?
What are the whispers?
Why was Dharma on the island?
How was Christian able to roam around the island?
Where did Smokey come from?
What do the numbers mean?
What does the donkey wheel do?
Who built it?
How are they all connected?
How did the others get to the island?
Why did the psychic tell Claire she HAD bored flight 815 and no one else could raise her baby? (My fav)
What caused the plane to crash?
Why was it so important to push the button?
What happened to Dr. Swans arm?
Whose eye did the tail section people find in their Dharma station?
What's the sideways universe?
How was time travel possible?
How did Locke survive such a vicious fall?
Who's Matthew Abandon and who does he work for?
How did Locke die?
What’s the deal with Sawyers note?
How are the characters connected?
Why is there a giant foot on the other side of the island?
What happened to the rest of the statue?
Who were ADAM and EVE?
Why does the island need a protector?
Why did Sun not want Jin to know she spoke English?
Who left the distress signal?
How did Rousseau get to the island?
Why was Libby in a mental institution?
Why was Hurley in a mental institution?
Who is Charles Widmore and why does he have such an interest in the island.
Why does MIB need to find a loophole in order to kill Jacob?
Why did The Others take Rousseau’s baby?
How did the passengers of 815 survive a plane crash?
Of course many others were left unanswered but for me it's better that way.
From imdb.com