When you go to a casino, say that a slot machine ate your money and didn't give you any credit. Generally just say that it was a five or twenty. If they check and say that it is working fine, argue with them civilly and say that you know for a fact that you put the money in and you will most likely get reimbursed for the money that you never actually put in.
This one is an obvious given. When you call a business or helpdesk and is greeted by a "Press button 1 to..." menu tree, repeatedly making the wrong choices (like mashing "9" when there is no choice 9) will often get you straight to an operator.
