What are dimples? And why do only some people have them?

Dimples are a generic name for indentatios on the skin. They are most likely to appear where the skin is most tightly attached to the underlying bone.

So those dimples we' ve long envied are actually an anatomical flaw!. And the tendency towards dimples seems to be hereditary.

If you want know more about dimples or Imponderables you can read Imponderables David Fleman