A guy goes into a store and tells the clerk, “I’d like some Polish sausage.” The clerk looks at him and says, “Are you Polish?”
The guy, clearly offended, says, “Well, 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? Would ya, huh? Would ya?”
The clerk says, “Well, no.”
With deep self-righteous indignation, the guy says, “Well, all right then, why did you ask me if I’m Polish just because I ask for Polish sausage?”
The clerk replies, “Because this is Home Depot.”
Explanation: The humor comes from the man’s long-winded rant about stereotypes revolving around the assumption that Polish people are not very smart., only for the twist to reveal that he’s in a hardware store, not a grocery store—making his request completely out of place and the clerk’s question totally reasonable.