I'm sure everyone has a story to share on this topic.
For me, it was several years ago, fishing with my son on the Blue in a Silverthorne, CO.
it was mid summer and the flows were low coming out of the reservoir. We were fishing just below the reservoir. I was fishing a small pool there and my son was just downstream. In the distance, we could hear the high pitched sounds of folks flying their remote controlled model planes.
Out of the corner of my eye, I saw a white blur and then saw a huge splash near my fly. One of the airplanes had lost control, run out of gas, and quietly crashed next to my fly!
Being in my waders, I retrieved the plane and held it for the owners who appeared over the bank of the river.
My son and I laughed about that for the next several days.