The lesson is almost always smaller and duller than the regret attached to it.
Aviation checklists get written after specific accidents, and what ends up on the card is often something like: confirm the flap setting aloud. Enormous grief, one flat instruction. That is the correct ratio, though it never feels proportionate to the people who were there.
Regret expands to the size of what happened. The lesson stays the size of what to do differently. Once you can state yours plainly, the rest of it is grief rather than instruction — and grief doesn't take direction, it takes time.