A doctor made it his regular habit to stop off at a bar for a hazelnut daiquiri on his way home.
The bartender knew the doctor's habit and would always have a drink waiting. But one day the bartender ran out of hazelnut extract, so he substituted hickory nuts.
When the doctor arrived, he took a sip and exclaimed, "This isn't a hazelnut daiquiri!"
"No, I'm sorry," the bartender replied.
"It's a hickory daiquiri, doc."