One of the most annoying things about the Wall is the people who try to sell you crap.  They will follow you almost the entire length (bare in mind this is a lot of up and down stair climbing) and pretend to be your friend, and then when you aren't expecting it, they will pull out a throng of T-shirts, books, and post cards to sell you.  I had been walking and chatting with a friendly little Chinese girl most of the way, and after she took this picture for me, she busted out her stash.  Needless to say, she had me fooled.