Arrive in London. What do you know. I'm the first one to arrive so I have to wait several hours for everyone else. Lucky for me their flight gets delayed.
Love that I'm spending X'mas in the airport. This better be worth it :)
Have an entire day's wait at the airport. Decide that taking the tube to London would be too expensive for an 8 hour layover. Try to sleep, realize the metal armrests are uncomfortable. Sit grouchily on the chairs counting down the time till departure. Watch everyone else sleep in jealousy.