Last year, the AV Club's Nathan Rabin came up with the idea of the Manic Pixie Dream Girl, and the concept has since taken off- even getting its own Wikipedia entry. An MPDG is defined by Rabin as "that bubbly, shallow cinematic creature that exists solely in the fevered imaginations of sensitive writer-directors to teach broodingly soulful young men to embrace life and its infinite mysteries and adventures."
Now, Rabin revisits the topic, talking about a couple of direct-to-DVD movies with MPDGs, including one with Lucy Liu:
It doesn’t help that Liu is pushing forty. Manic Pixie Dream Girls tend to be twenty-year olds with perky tits for a reason. If a fetching nineteen-year-old says, “Let’s play hooky, dress up like pirates and fly kites!” it’d probably come off as charming. But if a divorced, forty-three year-old mother of two proposed the same thing it’d come off as regressive and unhinged.