We on the committee are all imagining the things that could go horribly wrong at the conference. (Most recently: forgot to put together a list of changes to the program after it went to print. Thank goodness for revision history on the program DB! Else: CHAOS, MADNESS!)
But my time now is all on nitty-gritty organizational disasters. What goes wrong for you personally at conferences? Leave them in the comments, and let's get a top 10.
My contribution: forgetting my power cord!
P.S. There's a mall connected by skywalks to the Hyatt that has a store that sells power adapters for mobile phones. I bet you could find a laptop cord there, too!