It is hard to stay awake. Up at 9am or so on Monday, NYC time. Fly overnight with very little sleep. Arrive back in to London. Rush through Heathrow with a minute to spare. Fly on to Edinburgh. Your bag is thankfully first off the plane. Shuttle bus to car. Hop in car and drive home, confused about which side of road to be on. Breathe. Tired. Must stay awake. Go and buy some food. Eat. Tired. Must stay awake. Do the washing. Tired. Give up. Sleep.