Here's a little trick guaranteed to make your life more wonderful. My buddy MJ thought it up, but it's too good not to share.
When purchasing items from some stores (i.e. Home Depot, Radio Shack), it's standard store policy to ask you your postal code. Perhaps you want to protect your privacy. Perhaps you mistrust their motives. Or perhaps you find your real postal code to be rather boring.
The solution? Tell them "H0H 0H0".
It protects your privacy, and if it doesn't give the cashier a smile, you'll know they have no soul.