When a teen is teary eyed and snuffly, you predict there is bound to be some outside force such as a boy and some despairing detail like a broken heart. Most of the details of the previous sentence stand correct for the snuffles but for the outside force. The outside force in this case is cracked nail polish.
The worst thing any girl experiences are cracked nail polish right after a mani-pedi. A heart break does not necessarily have to be because of a boy. Apparently cracked nail polish sends the same chemical reaction to the brain making a girl touchy and moody.
Nail polish tends to crack when not applied properly. A good nail polish application is when you apply two coats of paint and apply the second after the first coat has dried.
Another reason for cracked nail polish is when it has not dried and you start doing your stuff. Nail polish is not a delicate accessory but it does need 20 minutes of tender love and care while applying and dang you are set for a good 3-4 days.