As the molecules go faster, they are more likely to bump straight out of the liquid and fly off to become a gas. The more molecules that bump out, the higher the vapor pressure. Now, if those molecules have big intermolecular forces like hydrogen bonding or london dispersion forces - when they bump into each other they're more likely to stick.
Often, spoon nails are a sign of iron deficiency anemia or a liver condition known as hemochromatosis, in which your body absorbs too much iron from the food you eat. Spoon nails can also be associated with heart disease and hypothyroidism.
Trauma, pt 1. Some doctors believe that repetitive trauma to the fingernails causes them to regenerate, or grow, at an accelerated rate. This means that people who bite their nails are more likely to have nails that grow faster than people who don't bite their nails.