What most people forget is that the past exists within each one of us only as memory. Memory has no objective existence. It is not existential; it is purely psychological. If you retain your ability to respond, your memory of the past will become an empowering process. But if you are in a compulsive cycle of reactivity, memory distorts your perception of the present, and your thoughts, emotions, and actions become disproportionate to the stimulus.
The choice is always before you: to respond consciously to the present; or to react compulsively to it. There is a vast difference between the two. And it can make the world of a difference.
If terrible things have happened to you, you ought to have grown wise. If the worst possible events have befallen you, you should be the wisest of the lot. But instead of growing wise, most people become wounded. In a state of conscious response, it is possible to use every life situation—however ugly—as an opportunity for growth. But if you habitually think, “I am the way I am because of someone else,” you are using life situations merely as an opportunity for self-destruction or stagnation.