Number 5:”Can you tell the difference between them?”
Not the most dire, but this one gets special consideration because of it’s recency. The context is that Barack Obama had just finished explaining how he had met with a spate of foreign leaders. Cue the uneasy silence and a barely perceptible eye-roll from the prince’s handlers.

Number 4: “How do you keep the natives off the booze long enough to get them through the test?”
Spoken to a driving instructor in Scotland in 1995, aggravating all of Scotland who then returned to their pints to calm their nerves.

Number 3:“You managed not to get eaten, then?”
Spoken to a backpacker in Papua New Guinea. Little did he know that the Papua New Guineans started boiling water in a cauldron right after this statement.

The foot doesn't cook well if it's stuck in the mouth...

Number 2 “Do you still throw spears at each other?”
Asked of an aborigine in Australia.
Why yes, your highness…please stand over there and let me demonstrate…

Just a little to the left your highness...

Number 1: “If you stay here much longer, you’ll all be slitty-eyed”
Spoken on a state visit to China in 1996.
And if you hang out with the prince any longer, a foot will grow out of your mouth.

Bonus:”You are a woman, aren’t you?”
Asked of a Kenyan woman in 1984, just after she had presented him with a gift. The woman secretly wished that she had given him a bottle of cholera instead of a hand woven hat.