While riding in the rain one nite I hit a pothole covered with water at medium velocity.
Air came out of the tube and I just swapped it out with a new tube. Next day I checked
the flattened tube and there were 2 small holes next to each other, classic pinch flat I suppose.
Quite different than the normal single hole I get with flats from glass and other debris.
I've had over a 20 flats, I think twice I never found the debris that caused the puncture.