I was once cussing at a stop and go driver, only for the driver to get out and point at her throat. She was choking on her toast. We got it cleared and she was okay.

Assholes seem to be more common than medical emergencies though.

He just saw someone with a mask and a bloody axe creep into the back seat of your car.

Maybe he just was honking to alert you of his presence to avoid an accident?

My Favorite human phenomena is that most drivers will use the horn when their safety could have been secured by applying the brakes