Aside from verbal/physical abuse a lack of encouragement to pursue and support their dreams whatever they may be. Many parents have their own ideas of what (they want) their children to focus on, do, be, or invest their free time. Life is a (personal) journey! Too often parents forget this. Unintentionally they say things in order to shoot down or kill their dreams (that may stick with a person for life). Nurturing a child's self-esteem is the foundation for instilling confidence. If your own parents aren't in your corner it's a challenge to learn to ignore them and overcome other naysayers. Parents are expected to be a child's first mentors. Thankfully there are numerous "self-help" books and courses!
Yes, I totally agree with you ,your past, as hard as it may have been , doesn't have to be a reflection of your future, it may be a long journey to overcome bad expierience but in the end we have the capacity to learn and grow.