The Recognition of Respect

I've spent the past couple of days contemplating how one develops self-respect.  I know to some degree it is formed from one's upbringing and positive role models, but what about people who have defied the odds and come out of crappy childhoods or never had someone to guide them in a positive light?  Where do they find their self respect?  How does it develop?  At what point do they decide to love themselves and live a life of dignity and integrity?  What about the people who are brought up surrounded by positivity and respect and hope, but live a life where they feel worthless and undeserving?  Is it a genetic predisposition?  Is it triggered by an event?  Is it a choice?  Is it a combination?
I believe my own self respect has reached peaks and valleys over my lifetime.  I know that when I'm in a healthy state of mind, I'm able to take better care of myself physically, mentally, emotionally, and spiritually.  I also know that when circumstances out of my control  have affected my daily life, I have questioned myself, beat myself up, and let myself down.  I know that for me, negativity is contagious and it takes an enormous amount of awareness and self control not to get sucked into that vortex.  I believe all of these things have an impact on my self respect.
In my darkest moments, I wasn't able to see myself as worthy of anything.  "I can't..." was my catch phrase.  I couldn't see myself succeeding in anything because I convinced myself that I wasn't capable, I wasn't deserving, and no matter how many people encouraged me that I "could," I didn't have enough respect for myself to even try.  It was in the moments when someone else would tell me I "couldn't," that something would change.  I felt the need to prove them wrong, to surpass their expectations.  Suddenly, the things I had doubted about myself, became things I prided myself on.  The more pride I felt about my accomplishments, the more respect I gained for myself. The more respect I had for myself, the more capable I became.  Over time, I became more aware of the limitations I had placed on myself.  
I have no degree or scientific research to base my knowledge or opinions.  I've never taken a psychology course, or studied the human brain.  The only place I can speak from is my own experience.  What I have learned on my own personal journey is that our upbringings, our genetic makeup, our life's events, and our choices all have an impact on who we become, but I do not believe that they define us.  I'm not sure the answers to the questions I'm asking are definitive.  I do believe that each of us has at least a smidgen of self respect deep within us, and whether we nurture it or ignore it, is completely up to the individual. I guess the real question is, which will you choose to do?