I have known many sorrows, most of which never happened. - Mark Twain
Why we limit our possibilities
Our brains are hardwired to look for patterns in order to simplify and classify what we encounter. When hurtful things happen, we anticipate the wounding behavior of others to protect ourselves from possible future wounds. We imagine others are thinking and feeling things about us that correspond to the wounding event(s). We start to organize our behavior around avoiding possible triggers, overcompensating by acting in the opposite way or surrendering to it. Our expectations contribute to co-creating future interactions that corroborate our assumptions.
The fascinating thing about this process is that most of it takes place in our own heads and outside of our conscious awareness.