This was a real revelation for me.
He described that process by which we create our reality in terms of:
arising sensory impressions becoming
paired with associations and memories to become
a sensation of pleasant/unpleasant
which is immediately paired with either desire (for a pleasant sensation to continue) or repulsion (wanting to repel an unpleasant sensation) which becomes
volition and then
He then grouped this sequence into two types of psychology, or karmic stages. Up to where sensation becomes desire/hatred is called 'resultant karma'--meaning results of all that has come before--memories, thoughts, associations. This is beyond the realm of moral judgment, it simply is. It's the shaping of perception and interpretation through the prism of that person's individual life history.
From the place of desire/hatred up through volition and action is the place of 'causal karma'--where action creates new "karmic outcomes".
The very exciting part of this is the notion that the element of choice can be introduced into this model, particularly at the 'gap' in the stage between recognizing pleasure/not-pleasure and it becoming desire/hatred. And this is where freedom from our habitual thoughts and actions can arise. He suggests meditation as the means by which to gain the awareness of that stage before a pleasant/unpleasant sensation turns to desire/hate. And with awareness comes the ability to choose.
I hope I didn't mangle Mercurious's excellent post too much in my summary, and I highly recommend you go to the post yourself because he explains it so much better than I do. The reason I included a summary here was to show it as a template that I put my own experience with my friend into to see what it would look like:
Talking to my friend, I mention that I’m satisfied that her son has worked off a debt he owed me. I feel a change in our atmosphere and she says something; I feel something more intensely
That is a form of sensory input that comes through my ears and eyes, and it is now being compared to memories and concepts I have stored.
She is not smiling;
In this case, immediately on receiving the sensory form, a basic sense of unpleasantness arises
Memories of other similar situations arise; memories of disapproval, memories of being surprised by unexpected negative emotions. An unpleasant feeling arises.
The unpleasantness is immediately joined by revulsion to push away this unpleasant feeling
I dislike my unpleasant feeling, I identify it with being disapproved of, of being unexpectedly hurt. I want it to go away.
Hating leads to volition, an intent to take action to dispel the negative feeling.
I resolve to talk
I follow through on my intent
I send an e-mail seeking to see if the feeling I’m having is real; seeking to find out if there’s a misunderstanding.
This is a karmic cycle where each of these steps is predisposing the next step. The next set of sensory forms, associations, hating, volition, and action take place, and they’re determined by the previous. On goes the karmic cycle.
Mercurious suggests that at the moment between my recognition of 'unpleasant' and my 'hatred' of what was unpleasant, I can introduce some 'space' into that gap. I can accept the existence of the unpleasant feeling and see it as merely a result of things that have gone before. Perhaps this is not a sensation which demands action. So, theoretically it was possible that I could let the feeling of unpleasantness in that moment with M pass, understanding that it’s a result of prior conditions within us both.
There is a curious feeling of vulnerability in the prospect of accepting a sensation as what-is, without being compelled to respond.
I guess the point of Mercurious's post is not that it is never appropriate to respond, but introducing that element of choice can mix things up a little, let us choose a path that's not merely a continuation of our past conditioning.