You'd think that with a team of makeup artists at their disposal, celebrities would always leave the house looking flawless. But from the look of these photos, some of them may need to rethink their makeup choices. Check out these stars' best and worst looks, side by side. It's a perfect reminder that we all, even celebrities, have good and bad beauty days.

Christina ignored one of the first rules of makeup -- which is to only play up one feature at a time. Instead she had dramatic eyes, lips and cheeks, far left, which was just too much. In the other photo, she sported toned-down eyes and cheeks, making her red lips the focus -- much better.

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Images: Getty Images, taken in New York City on March 23, 2007, and in Los Angeles on September 16, 2007

Red eye shadow is rarely a good move. It either makes you look tired, or in Tyra's case on the far left, demonic. She made much nicer use of warm shadows in the other photo.

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Images: Vinnie Zuffante/Startraks / Getty Images, taken in Universal City, Calif., on March 6, 2004, and in Washington, D.C., on January 12, 2008

Denise put on her "leave it" face, far left, for a Pussycat Dolls performance, and she did look like a doll ... an inflatable one (wink, wink). In the other photo, she appeared soft, natural and human (always a good look).

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Images: Getty Images, taken in Las Vegas on June 9, 2006, and in Los Angeles on June 8, 2008

We won't criticize Amy's signature eye makeup; it's part of her persona. But we will use these photos as an example of the value of foundation (and a good night's sleep). The photo on the far left also showed the need for a good lip balm.

What do you think? Talk about her looks on our message boards.

Images: Getty Images, taken in London on February 29, 2008, and in Austin, Texas on March 15, 2007