One day, a blonde went into an appliance store that was having a sale on TV's. She walked up to the counter and said to the clerk, "I would like to buy this TV."
The clerk replied, "Sorry, I don't sell to blondes."
So, The blonde dyed her hair brown and returned the next day. Again, she went up to the counter and said, "I would like to buy this TV."
And again, the clerk answered, "Sorry, I don't sell to blondes."
Puzzled, the blonde asked, "How did you know I was a blonde?"
And the clerk said, "Because that is a microwave."