So every day on my way home from work, I stop at this little neighborhood bar and have a beer. Two days ago, as I'm sitting there, just me and the barkeep, who was barely awake, a duck walks in and asks him "Do you have any grapes?" "No, we only serve beer here." Yesterday, same duck walks in..."Do you have any grapes?" "No, I told you yesterday, we only serve beer here. Try this stunt again, and I'll nail your bill to the bar. Now get out." Today, sure enough, in walks the duck. "Got any nails?" "Nope." "Got any grapes?"