@Durwin

I believe what you live and learn in your life kinda defines who you are. Ofc there are exceptions in life and the "base" personality of each other is a big factor to this and that's exacly what differentiates each other. Take this example... someone that went tho a very harsh and painful life can become a person that is extremelly understanding and helpful since life was a bitch to him/her that person just want to try and make others life better BUT, the opposite could also be the case and he/she can become someone bitter and shifty to give a taste of what life gave him/her to others.
So I would say that our core, defines how we react and become after "shit hits the fan".