The length is perfect, and sleek-straight hair is a great choice for the round-faced. But a deep side part with the bangs pinned firmly back? That would be a no. If your face is round, bangs are a great choice. They can hit the brows or even be a bit longer and swept to the side. They help create the illusion of angles to the face.

Shoulder-length hair is great for round faces. Subtle waves that don't add volume at the sides work great for round faces. Notice the bangs that sweep at an angle across Akerman's forehead. This breaks up the rounded curve of her hairline and give the face angles it didn't have before.

OK, sure. Alba's worst day is our best. But this cut is nonetheless a perfect example of a bad choice for women with square faces. While a medium-length hairstyle is great, bangs rarely, if ever, flatter a square face. Bangs are great for round faces because they create angles. So it follows that they're not so great for square faces, because they create more angles on an already angular face.

A "long bob" is one of the best options for the square-faced woman. The angled bottom and face-hugging sides soften the jawline. A center part further de-emphasizes angles and facial width.

It helps to be drop-dead gorgeous and quite nearly perfect if you're going to break every rule of hairstyling for your face shape. We're talking about Washington in this photo, of course. The rest of us with heart-shaped faces need to remember that it's best to avoid medium-length hairstyles that emphasize the forehead and have lots of volume at the sides.