Proof That Girls Are Evil:

First we state that girls require time and money.

Girls = Time x Money

And as we all know, Time is money.

Time = Money

Therefore:

Girls = Time x Money
Girls = Money x Money
Girls = Money²

And because Money is the root of all evil.

Money = ÖEvil

And as such

Money² = (ÖEvil)²
Money² = Evil

So finally, using substitution, we are forced to conclude that:

Girls = Money² = Evil
Girls = Evil

Click here for more fun!