Quote Originally Posted by Hamish
There are more than enough long-faced, miserable, sour-pusses in this world without me going around with an unsmiling expression on my face.
All of what Hamish said is correct - but if you absolutely must get through the crowd to handle something on the other side (I do security stuff for reenactment gatherings, usually on the night shift) then the grim face with the great kilt is usually a lot more effective than the Princess-Bride-Fezzik-style bellow of "EVERYBODY MOVE!"