Girls are evil 
Found the basis for this on Bash.org… pretty sure it is actually an old thing - but I still like it:
Girls = Time x Money
Time = Money
Girls = Money x Money = (Money)2
Money = root(evil)
Girls = (root(evil)2)
Girls = Evil
Or…
you can say girls = (root(evil)2), so girls = |evil|
or girls = absolute evil
I can live with that.