Yeah, I am not great at visualizing 3d space, but I have thought enough about BJJ that I can map it all back out as well now. Plus you learn the heuristics. Usually it is something small. Lost a grip, allowed a grip, let something get loose in your half guard that lead to being cross faced, passed, etc. Often I know right away now when something is bad, though it takes a little work to figure out exactly how it happened (upper belts are sneaky like that) and unforced errors happen as well, at least those are easier to figure out :)