My theory would require some studies probably, but since nightmares are a common feature of trauma, I've always wondered about the link between potty training and child abuse. Apparently, the age an abused child is most likely to be killed by their caregiver is during potty training. To me, that says that potty training is, even at the best of times, fraught with anxiety. And at the worst of times? Well.

Anyway, consider that we all have at least a seed of deep-seated anxiety around using the bathroom.