A duck walks into a library and says to the librarian
"Hey Mister! You got any bread?"
"No, we're a library. We lend books out, we don't sell bread" replies the guy, "try the bakery down the road". The duck walks out.
The next day, the duck walks into the library and again, he asks
"Hey Mister! You got any bread?"
The librarian is a little confused, but replies
"No, we're a library. I told you yesterday, we don't sell bread. Try the bakery". Again, the duck walks out.
The same thing happens the day after, the day after that and so on, for the rest of the week. It finally comes to a head when the duck asks for some bread, and the librarian bursts out "LISTEN YOU LITTLE BASTARD! WE DON'T SELL ANY FUCKING BREAD, GOT IT?!?! IF YOU ASK ME ONCE MORE, I'LL NAIL YOUR FUCKING BEAK TO THIS DESK!"
The duck, a little taken aback, looks around the room at the surprised readers, before looking back at the librarian.
"Fine." He mutters, "Have you got any nails?" The librarian looks at him, trying to see the connection.
"No... You need the hardware store, it's next to the bakery".
"OK then" says the duck, looking the librarian straight in the eye...
"Have you got any bread?"