Everyone has valid points, but this is an hour show, well not fully, but let us say 40 minutes and the writers have to tell a story. If they got into the detail we all wanted this show would continue ad nauseum and we still wouldn't like it.
I can't recall one show where the continuity was to the detail we may look for. And if there was one it didn't last very long. We focus on the main characters to get through the story and yes all the things Juggy and others mentioned happened, but do you recall the exact details of season one? Let alone what may have happened in our own lives a week ago. Well, okay our own lives may be more important.
My point is I think we all agree that there were topics we would have expected them to discuss in normal conversation. But they didn't.
Just like Jack and Claire not knowing they are siblings. Or Jack querying Sawyer further on his meeting with his Dad and how his Dad got there. Yes, the numbers, never pursued or Hurley's money or how or what these folks did before the island or why they were going to LA. Or Locke every having a discussion with Sawyer about his past and thanking him for killing his dad. Or anyone asking Kate, Sawyer or Jack what was done to them when they were taken captive.
I am not sure they even discussed why the hatch was imploded.
Oh Alaskas I think Claire choose the beach as she didn't want the caves, I think they, or most thought it was the obvious place to be found and the "safest" place for them.
We find tidbits and there are nuances that make us scratch our heads.
Instead the writers catapulted them into seeking the islands secrets, flashbacks, forwards etc. The writers have a course and they are sticking to it and maybe at the end, we will find them sitting around a campfire talking about things we wanted to find out most. As a detail person it is frustrating, but it is comforting to know we are all in good company.