Teachers are mistake masters. Teachers correct mistakes all the time and then if they themselves make mistakes it is best practice to reflect on the mistake and if needed re-teach the lesson for the betterment of the students.
In my courses mistakes fall into a few categories red pen, eraser, and start over. Red pen mistakes are ones that are found on summative assessments, tests and quizzes. Eraser mistakes can be found in the formative assessments, class work and group work. Start over mistakes are usually found in the lab, rebuilding an engine and making a fresh sausage.
One of the biggest mistakes from the last school year was a fishing trip for my wildlife and fisheries class. We didn’t catch a single fish. I don’t even think there was a sizable nibble on anyone’s line. The students enjoined the afternoon out of school but the effectiveness of the teaching was not as well done because of the lack of fish. This mistake lead to more time in the classroom and a lack of resources for a taxidermy unit.
Fish or not, this is how I would like the next trip to go. Students get off the bus and everyone gets out a fishing pole and some tackle. Before casting into the water everyone has some bait to fish with and can demonstrate how to properly bait their hook. Then, still together, we go to the water and everyone demonstrates how to cast. During this time we review the etiquette of casting. If a fish is caught during this practice, have the student who caught it describe to everyone how to remove the hook. (Having a collection of bananas and a few fishing hooks at school would be good practice for the day before.) Once students have demonstrated the skills needed to fish then they are free to fish for the rest of the trip.