A duck waddles into a bar and hops on a stool...

The bartender snarls, "What'll you have?" 

The duck says, "Got any grapes?" 

The bartender spits and says "We don't have grapes here, we serve drinks, now get out!" 

The duck hops off the stool and waddles out. 

The next day, the same duck waddles into the same bar, hops on a stool, looks the bartender in the eye and asks, "Got any grapes?" 

The bartender, irritated, says, "I told you yesterday we don't serve grapes here, we serve drinks, now GET OUT!" 

The duck hops off the stool and waddles out. 

The next day, the same duck waddles into the same bar and hops on a stool, looks at the bartender, and asks, "Got any grapes?" 

The bartender, infuriated, pounds his fist on the bar and yells at the duck, "I told you two times we don't serve grapes here, we serve drinks! If you ask me that ONE 
MORE TIME I'm going to nail your beak to the bar! NOW GET OUT!" 

With that, the duck shrugged, hopped off the stool and waddled out. 

The next day, the same duck waddled into the same bar, hopped on a stool, looked the bartender in the eye and asked, "Got any nails?"

The bartender, puzzled, said no. 

The duck then looked him square in the eye and said, "Got any grapes?"