Blues as it washes! But what if you dont want to change the hue of the garment? What if you don't like the color blue? Don't be silly. It's a term that means . . . well, yes, it ads blue, but there's a reason.

White fabrics acquire a slight color cast after use (usually grey or yellow). Since blue and yellow are complementary colors in the subtractive color model of color perception, adding a trace of blue color to the slightly off-white color of these fabrics makes them appear whiter.

The wikipedia enry also notes:

Solid bluing is sometimes used by hoodoo doctors to provide the blue color needed for "mojo hands" without having to use the toxic compound copper sulfate.

I hate mojo hands. Doesn't everyone?