Why can't it just be that it was a part of you it could be, but assuming that in general implies that your behavior is genetic and there is nothing you can do

Why can't it just be that it was a part of you it could be, but assuming that in general implies that your behavior is genetic and there is nothing you can do to change it. which i do not believe to be true. your behavior is formed by your environment, and you can change how you behave.