I have often talked in our shop how if your cup is too small and band is too big, its like a yarmulke (no religious disrespect meant - just an illustration of small) with a chin strap rather than a nice stocking cap that comes down over your ears. This blogger has some great photos of this idea.

Bra Science - 11 Signs You May be Wearing a Boob Hat

Do you feel unsupported by your bra? That it squashes your boobs down instead of lifting them up? Or maybe you feel that your bra is just a useless garment altogether, costing quite a bit of money considering it just doesn't really do anything? You may be wearing... a boob hat.