The classic Jack Nicholson scene
Here.
For the record, never in my life have I run across any restaurant of any caliber where they wouldn't happily alter my order to taste (within reason). Sometimes they didn't have something in stock, and sometimes my special order would cost a little more (like substituting a shake for a soda in a combo, or adding mushrooms to a steak), but nobody has EVER told me I couldn't have something because it wasn't exactly what was printed on the menu.