An actor who ‘plays’ his characters as if having continual profound insights into the past, always and invariably understanding it , and even worse, all too willing to feel and reveal its emotional effect on his present conflict(s) is giving a starkly dishonest performance.
It must be remembered that a character speaks about the past only because she has to
speak about the past. In real life, we think about the past only because the present lacks fulfillment. The past is re-visited only because the present conflictual stimuli have brought the (so-called) “past” emotions, the mud of our lives, to the surface. We are forced to consciously review them, to deal with them, learn from them, to modulate them, to mollify them, to operate better by learning from them--and we only do to achieve our present objective.
An actor all too willing to have their character reveal the past should consider this: If the character had been so eager to talk about the past now, why didn't she do it sooner? Why wait until now? What is it that makes it so important to talk about it now?
A character only reviews the past under duress, under the urgency of the moment, of having to win. The character reveals the past to the another character (and herself)only in order to forestall the other character (or herself) from learning even more about herself, from discovering even deeper and more expensive self-truths…and all of this only in order to get what she wants from the other character as cheaply and expeditiously as possible.