Another is to order something, then half way through say it tastes "funny" and ask for something else, thereby getting yourself both a starter and a main for the price of one main. Usually in these instances, it is impossible to get a customer to define what "funny" actually means with regards to the taste of their food.
My favourite though, are the people who "know the owner" or for whom "the other guy always discounts our meal". To these people I say.....read the title of this post.
A couple of days ago at work, two of these "special" people came in and were ordering coffees from one of the waitresses. When she told them how much they had to pay, one of the ladies insisted that "the guy who is normally here" only charged them $3.70 for their coffees. Now, if you are going to try to scam the young waitress, especially for the sake of 50c a mug of coffee, at least do your homework first. On the occasions when we do discounts, it's either 10% (in which case the mug would cost $3.80), staff price ($2.00) or mug for the price of cup ($3.60) NONE of our discounts would make your coffee $3.70, we don't have a button on the til to charge you $3.70, I am full time and have never seen you before, and no, you are not getting a discount!
The "I know the owner" thing won't work with me either. If you really knew the owner, you would know there is no way he has offered you a 50% discount for your meal. "Knowing the owner" will not get you a seat faster on a busy night, it won't make a menu item you liked off the old menu suddenly available even though we no longer sell it, it won't get you an extra shot of alcohol in your cocktail or a free appetizer or your ipod plugged in to the speaker system. It will get you laughed about in back of house when we are all imitating your pathetic attempt to big note yourself.
Just remember, you are no more special then any of the other customers I am serving, and this is a business, where making money is our goal. If you want charity, you're in the wrong place. Just pay up buddy.