Flying from the Pacific time zone to the Eastern time zone is only a 3 hour difference, but being at the visitor badging office at 7am ET, which means waking up at 5:30am ET, when your body thinks that it is 2:30am causes you lose a step. You try to go to sleep at 10pm ET because you have to get up at 5:30am ET, but can’t fall asleep until 10pm PT (1am ET) and you still have to get up 4-1/2 hours later wears you out.