In this era of perfect tresses, when there's no shame in hair extensions, there remain a few actresses who go for blunt whack jobs. Gina Ash of Fairfax writes in: "Can you tell me why certain women in Hollywood who are lauded for their beauty -- such as Sharon Stone and Annette Bening -- seem to have styled their hair with a weedwhacker? Is this their way of saying, 'I'm so good-looking that it doesn't matter what I do with my hair'?"

Bingo. There is nothing so triumphant as having a bad hair day and still having everyone around you affirm your singular style. It can do wonders for the fragile celebrity psyche. (And judging from occasional trips to the 'burbs, I see the weedwhacker thing is catching on -- a look suited to harried but zanily gorgeous moms everywhere.) The mistake is to chop off your hair while your career is at a sensational zenith. (This is why Jennifer Lopez and others wear short-hair wigs when the role calls for it.) You want to save the big shears for the worst times: divorce, gossip, box-office flop. That's when you want to change the subject.

But sometimes the big chop happens off schedule. At Cannes in May, photographers went ape at the sight of actress Natalie Portman with a shaved head. Only bared breasts have more power to elicit a collective, eye-popping "wha-hunh?" in red-carpetland than the unveiling of a drastic haircut. In Portman's case (as with Sigourney Weaver and Demi Moore before her), the actress has gone Sinead-style for a movie role: She'll play a terrorist who blows up the British Parliament in an adaptation of the dystopian graphic novel V for Vendetta. (Why anyone would cast her in an effects-heavy action picture after her evident boredom with "Star Wars" is a puzzle. Blue screen work is not her forte.) The first peek at her chick fuzz head was sort of endearing, on the precept that nothing so superficial as hair can distract from the essential allure of a pretty woman. Much work has been done in the area of boosting feminine baldness into the realm of the exotic and proud, from runway models to cancer survivors.

But then the letdown set in. As more pictures of Portman hit the wires, she looked worse and worse. She began laughing too hysterically, and her mouth opened wide as her face, until Edvard Munch could have painted her portrait.