Shower
Have you noticed that right after Locke returns to the hotel in the begining of the movie, he switches on the shower, water is running and then for the rest of the scene, he forgets about it?
He drinks water from the glass and then goes to the next room where he finds Robertson dead. All this time the water is still running (imagine the scene: in the middle of the desert, Locke is spanding the most valuable think!). When he returns to his room trying to change photos in the passports, the water is not running anymore!!!
Obviously, the whole hotel tank was been left without water by Locke who does not care.
When i watched for the first time the movie i was astonished by the lst scene. Now i cannot forget the water spent without reason.