I learned the importance of checking all the planes before a flight.
I took one of the small park flyers out and had a great time. When I came back the house. I put the plane down and noticed that the elevator had come right apart from the wing. It appears that it was a bit of a manufacturing issue as the paint is also coming off the wing. But I would not have noticed this if I didn't look at the plane. I could have easily went to the field and crashed it the next day.