A blonde walked into an electronics store and said to the salesmen: “I want that tv.” The salesperson shook his head and said, “No, we don’t sell to blondes.”
So the blonde left and came back with her hair dyed brown and said: “I’ll take that tv.” Again the salesman said: “No, we don’t sell to blondes.”
So she left again and came back with her hair dyed black and said: “I want that tv.”
But the salesman still said: “No, we don’t sell to blondes.”
Finally the blonde got fed up and said, “That’s it! How’d you know I was a blonde?!” she asked. The salesman answered: “Cause that’s a microwave.”