Here's my best attempt at making a list of unanswered Lost questions. I think this list speaks to why season 6 was such a disappointment for those of us who really loved the show. Shame on you, lazy writers.
Who is Alvar Hanso?
Does Sun's dad have any ties to the DHARMA Initiative and/or the Hanso foundation? Did he know about the island?
Who was running all the things in Ann Arbor? What was in Ann Arbor?
Who were the DeGroots?
Why the conceiving issues on the island?
What was the DHARMA initiatives motives on the island?
Was it smoky in Jacob's cabin all those years giving orders to Ben? If so, why did Jacob let him do that? Was Jacob just observing all the goings on to see if Ben would be "good" in the end?
What was Libby's purpose? Was she working for Widmore? Or was it just a random coincidence that she gave Desmond the sailboat that brought him to the island?
Please explain the map written in invisible ink on the door in the hatch.
Why was Aaron supposed to be raised by Claire only?
WHY WAS WALT SPECIAL??!!!!
What were the rules between Widmore and Ben? Why did Ben break the rules at the end?
How did Ben have unlimited resources and money off island? Who was supplying him with these resources?
Was smoky controlling all the ghosts on the island? Was he the ghosts?
What was the purpose of the temple?
Why did the water turn brown?
What happened to ben in the temple when he was little?
Why didn't Richard tell Ben more about the island?
How did the others get all the food? (Ben's crew who lived in otherville)
What happened between Kate and Ben at the beginning of season 3 (or 4, can't remember), when he brought her onto the beach for breakfast and told her that the next few weeks were going to be very hard on her, and then she came back to the cages all beaten up and bloody? What did they discuss?
Why was Ben getting Sayid to kill all those people? Who was the economist?
What was Illana's background? Who were the people in her group and what did they believe?
What was Desmond's sacrifice? What happened to little Charlie?
What happened to Miles, Lapedius, Richard, and Claire?
Why was the lady at the hotel in Africa scared of Ben when he checked in?
What happened to Anna Lucia?
Why did smoky selectively kill some, but not others?
what was the point of the polar bears?
How did the polar bear get to the desert for Charlotte to find?
What did Eloise know? Why did she know so much? Why did she eventually leave the island?
Why was Desmond immune to the electromagnetism?