Why do I bite my nails? I REALLY don’t know!
I once posted an answer to this question on a different thread, but it didn’t get approved. I assume it was because of a certain word, so I’ll change that word and see if it gets through:
According to Freud’s theory of personality development, a fixation on nail biting can be a maladaptive practice developed because of a failure to properly negotiate the Oral Stage.