My mom died when I was 15 and as I grew up, I began to feel guilty for being a typical selfish child. I viewed the world through my own perceptions and never really knew my mom as a person. I spent a lot of time feeling guilty over that - not due to strict upbringing or religion - but mostly because at 15, moving in with my aunt and uncle - my aunt told me (with raised voice) that I was the most selfish individual she had ever met.
At the time, at age 15, she may have been right but it was wrong to tell me that in that way because that guilt and that hit to my self-esteem lasted a long long time.
I got over the guilt, but it took years and I got over being a selfish teenager but that took less time--it was the normal progression of age that taught me to put others first.
Words have tremendous impact on youth--wish more parents could remember that.