Lie: "I was born with this amazing thick/glossy/healthy hair."

OK, we all know celebs use hair extensions. They just don't like to talk about it. So, when we see a star walking the red carpet with fabulous hair, just know it took hours of styling, elaborate hairpieces, extensions, and tons of products. (Reason number 524 that I love Michelle Williams. You know she's not faking anything with her pixie cut.)

And when celebrities magically crop their hair, then grow it back in a month? Yup. That's fake too. Scientists say hair grows at about 1/2-inch a month, which is why Katie Holmes can't have a bob one month, and long hair the next -- at least not with her real hair.