A doctor walks into a bar at around 5:03 pm and asks the bartender for a hazelnut daiquiri. He does this every day for three weeks, always coming in at 5:03 pm. Picking up on this habit, the bartender always has a hezelnut daiquiri at the doctor's usual place by 5:03 pm. At the end of one day, the bartender runs out of hazelnut extract. Thinking quickly, he throws together a daiquiri made of hickory nuts and sets it down in front of the doctor's usual place. At 5:03 pm, the doctor sits down, takes one sip of the daiquiri and says to the bartender, "This isn't a hazelnut daiquir." "No it isn't," the bartender admitted, "It's a hickory daiquiri, doc."