Magic Mirron
There once was a magic mirror which would kill your if you lied to it.
One day a brunette was doing her makeup and said to herself "I think I'm the smartest woman ever!" She immediately dropped dead.
The next day a redhead was doing her hair and said to herself "I think I'm the prettiest woman alive!" She too immediately dropped dead.
Finally, the following day, a blond was flossing her teeth. She stopped and said to herself "I think," and dropped dead.
One day a brunette was doing her makeup and said to herself "I think I'm the smartest woman ever!" She immediately dropped dead.
The next day a redhead was doing her hair and said to herself "I think I'm the prettiest woman alive!" She too immediately dropped dead.
Finally, the following day, a blond was flossing her teeth. She stopped and said to herself "I think," and dropped dead.