I don't think I could have stayed as calm as you. Well done for keeping cool! I imagine I would have also rescinded my offer to work on it at all, given he sounds like he'll expect every future issue to be fixed 'to do everything for the customer'.
Sounds like a potential future nightmare to me!
Hope all does go well though and that he was just having an off day due to the car troubles.
I thoroughly applaud your approach to work and life. Sounds like you keep an entirely sensible balance.