No Nos at Customs

• Walking slower than 30 mph when you leave the plane, if you don't want to be stuck at the back of the line


• Asking questions of anyone walking at 30mph


• Asking for permission to switch to another line because you are "in a hurry" (5-minute lecture from Custom Officer, interspersed with "everyone is just doing their job", likely to ensue)


• Using cellphone in front of Border Control Officer


• Filling out forms - which were handed out on plane - near the front of line while waiting to be called


• Not having the right amount of grease on your fingertips to enable speedy fingerprinting


• Asking which direction to exit after you have been cleared through the line

What other No Nos exist? Thoughts?