A blonde walks into a store, points toward the shelf behind the cashier, and asks, "Can I have that TV please?"
The cashier responds, "Sorry, I don't sell to dumb blondes."
The next day, the blonde comes back with a brown wig on her head and asks, "Can I have that TV please?"
Again, the cashier responds, "Sorry, I don't sell to dumb blondes."
The next day, the blonde comes back after having surgery to change her face and dying her hair and asks,"Can I have that TV please?"
Once again, the cashier responds,"Sorry, I don't sell to dumb blondes."
The blonde, furious, asks, "How do you know that I'm blonde?"
The cashier says, "Because that's a microwave."