Can be used to delay a particularly embarrasing moment or if you're lost for words, like uh.
Can be used to answer an awkward or idiotic comment.
All purpose response to any situation.
Fiorella: Are you ready for some some hot, crazy lovin'?
Fiorella: Why did you eat my all my damn sushi?
Mike: Yeeaah, about that...
George W. Bush: They misunderestimated me!
Troy: My hair's on fire. AAAARRRRRRRRGGHGHGHGH! My skin is burning!!!