I always think I know what's going on psychologically during the course of an audition, but then again, stress and anxiety do amazing things to us and when we try to recall them later, little can be "learned" from the experience.
"What'd you learn?" "Well, as long as you learned something..." "We learn from our experiences." No no no. Shut up. Because what you learn is rarely what you actually do or use in life. I don't mean that pessimistically, really. At least for me, 99% of what I actually DO is in response to a stimulus. It's impulsive and reactive (and ideally, the outcome is on par with executing an impossibly witty comment: victory).
However we can't win 'em all.
So in the instances (of which there are many) that things just don't work out or the feedback was ambiguous and we're just not really sure what the response was or will be, looking back and reflecting on the why's and what if's is a colossal waste of time. First, because we can't relive it and second, because we're never going to really be able to recall what was coursing through our minds and/or bodies at a moment that mattered. Because if they really mattered...well, you get my drift. At least for me, stress and emotions are far too formidable and turn my brain to mush.
So taking auditions as say, a random and potentially uninteresting example to 99% of the population, there's no question I usually want the job for which I'm auditioning and my competitive spirit and expectations of myself are in full gear. Thus, getting in the car afterwards and rehashing it over and over in my mind is totally pointless due to the fact that I've just been in a highly stressful situation.
So I guess the point of all of this is that a) we don't learn anything from our auditions other than to speculate on what we think we did or what we think the producers/casting directors/etc were thinking as they stared blankly through our souls, and b) under duress, there's little point in trying to accurately decipher play by play what the hell just happened.
And finally, to avoid this seeming like a negative outlook (it's not, I swear), when it comes to this crazy game of instincts called acting, everything we take away from it needs to be just that: going with our gut. It either feels right or it doesn't.
Adjust accordingly :)