Can you read Worried Water?

You can learn to read Worried Water for danger.
Once I was coming across an unfamiliar Canada lake one day I dropped from half throttle to idle speed and none too soon. I had seen what I call worried water and there was a reef about a foot under the surface. I'm sure many a prop and lower unit have been lost on it to unsuspecting fishermen. Wing dams will do the same thing. https://www.youtube.com/watch?v=JnZUSp2NKnA

Sometimes the surface changes are easy to see and other times less so. If in doubt slow down and use your depth finder until you are familiar with the area.