The one pointed at my face by a Nassau Co. NY police officer in 1970.
I was young, 22, but already working as a state peace officer. He saw my gun when my shirt pulled up while I was bent over a car engine trying to diagnose a problem on my new 340 Duster.
He assumed because I looked young I had no right to carry a gun. He quietly came up behind me, and I heard a revolver being cocked. No request to ID myself.
When I turned slowly around, he had the cocked gun pointed at my face. The hole at the end of the barrel looked very big and was all I could focus on. That's when he finally asked why I had a gun.
I was furious, but too young and stupid to file a complaint. I was not from that jurisdiction and was told not to by older brother officers who believed a LEO could do no wrong.
I do not subscribe to that belief.