Some gardening myths are wild to me. Many websites and publications tell you not to spray water on the leaves of plants during the daytime because it can cause sunburn. The idea is that the water droplets will act like little magnifying glasses and focus the rays of the sun on the leaves.
This has been proven wrong in recent experimental trials! The water droplets form an ellipsoidal shape which does a poor job at focusing the light. And the water making contact with the leaves actually cools down the leaves, counteracting any kind of light focus.
But also from a conceptual, real world standpoint, it just doesn't make sense. Many places have summer showers where the sun is out shining 30 minutes later. If the sunburn hypothesis were true, then vast swaths of the planet would be devastated every time this happened.