"Then there is the perfect head but you think you need to get that one last chip........thwack and it busts in half."
Bone,
You can always tell when someone has really done it. That sentence right there spells out the whole experience for me. That and blood dripping from all the little nicks and cuts.
Caution: Do not flintknapp anywhere near the trail that leads to your mailbox (that you just might be walking barefoot down some morning on your way to get the paper and then wonder why you're leaving bloody footprints on the carpet later)