Today I considered pouring a cup full of hot coffee (straight out of the kettle) on to my forearm.
The test would be to see whether I could hold my arm in place and resist the reflex to pull it away from harm.
The next trick would be to ignore the first-aid recommendation to shove the burn under cold running water. I’m pretty sure I’d end up with an exciting scar to show my grandchildren.
Some deeper instinct stayed my hand.