Man with a German Shepherd dog goes into a bar and sits down at
the counter. Bartender says, You cant bring that dog in here!
Man says, But this is a Seeing Eye dog! Bartender says Well, OK,
then I guess it can stay.

After a while, the man and the German Shepherd get up to leave. As
theyre going out the door, another man with a Chihuahua is coming
in. First man says, The bartender wont like you bringing that dog
in here, but just tell him its a Seeing Eye dog and then itll be
OK. Second man looks dubiously at his tiny Chihuahua, thinks
a fews seconds, then thanks the first man and goes on in.

Bartender says, Hey! You cant bring that Chihuahua in here! Man
stares straight ahead and exclaims What! They sold me a Chihuahua?!