Waterloo

A very thirsty man goes into a bar. As he's sitting down, he hears the man next to him tell the bartender, "I'll have another waterloo."
The bartender gives the fellow a tall, well-iced drink, then asks the newcomer what he would like to drink. Thinking the other man's drink may be a specialty of the house,
he says, "I'll have a waterloo, too."
The bartender gives him the tall, well-iced drink and the customer takes a big drink.
"Hey," he says. "This isn't any good. It tastes just like water!"
The man next to him looks at the bartender and says, "Well, it is water. Right, Lou?"