I think it is a heartfelt hunger to sort out all the compressed confusion that comes with pain and impact.
We all walk around years later wondering "What the hell happened there??" and we sometimes have a dozens of these mysteries hanging around waiting to be understood. Sure we can shove them off, but the mystery doesn't really go away, and they can all zing back into full play if we let ourselves get a little under the weather.
Sometimes just walking through it enough times can at least make it clear where ya went off the path, or whatever jammed the thing together.