More evil

Baby names are important. The name will follow your child for the rest of his or her life.
It's okay to pick a name that has cute diminutive forms: Johnny and Suzy can still be normal, well-adjusted people when the mature into John and Susan.
Nicknames are fine, too. We all have nicknames.
Please, please, please do not make your favourite nickname into a legal given name. That's a form of child abuse, and will no doubt unlock one of the seven seals of the apocalypse.

(Obligatory link to the list.)