School can be particularly traumatizing due to teasing by other children.
Some people do not like to reminisce because of traumatizing experiences.
Teenage years can prove even more traumatizing in the looks department if you're not steered in the right direction from the start.
Going cold turkey on the morning donut and Friday night beer can be a traumatizing event, but the cravings typically subside considerably once you've suffered through the initial withdrawal agony.
The causes of PTSD vary, but the common factor is usually a traumatizing event.