A customer asked,  "In what aisle could I find the Guinness ?"

The shop assistant asks,  "Are you Irish ?"
The guy, clearly offended, says,  "Yes I am. But let me ask you something, if I had asked for Italian sausage, 
would you ask me if I was Italian ?  
Or if I had asked for German Bratwurst, would you ask me if I was German ?  
Or if I asked for a kosher hot dog would you ask me if I was Jewish ?  
Or if I had asked for a Taco, would you ask if I was Mexican ?
 Or if I asked for Polish sausage, would you ask if I was Polish ?"

The shop assistant says,  "No, I probably wouldn't."

The guy says,  "Well then, because I asked for Guinness, why did you ask me if I'm Irish ?"

The clerk replied,  "Because you're in Bunnings."