Because it's nessecary.
When you and another person walk past each other and high five. Looks coolest if you don't make eye contact.
Often dramatically executed by doctors and professors to point at something on a chart. See also Pretentious.
Especially fun to do when it's snowing outside See also Weapons.
Kind sir, might you lend a hand and add a funny thing to do?
Go ahead, grab your sisters Miley Cyrus mixed cd and send it off to microwave heaven. Looks wicked cool too. See also Food.
On long road trips as a child, I used to shove kleenex in my mouth, put my hands behind my back, and act as if I was tied up in the back seat of our mini-van. See also Pranks.
Hard... but possible.
An ancient form of entertainment. Probably the most famous magic trick of antiquity. Even in the 21st Century it never fails to dazzle and amaze.