I was 12 or 13 when I first repaired a flat by myself. I had to walk my bike a half mile to the local gas station for some air. That was uneventful and while riding my bike home I stopped to watch a guy flying a gas powered model airplane on a tether. Around and around it screamed until all of a sudden BANG!!! and the plane augered into the ground somewhat spectacularly, with pieces flying everywhere. Of course it was my new inner tube that had exploded from being twisted and the pilot must have jerked the tether when it startled him. He and his friends were much older than I was and I realized that I might be in danger of a beating if they figured out that the explosion was from my tire. I tried to look just as bewildered as they did. I was fortunately far enough away from them that they couldn't see that my tire was flat and I was able to innocently walk my bike away from them without being accosted.
After I figured out what happened to that tube I learned to make sure freshly changed tubes weren't twisted before fully inflating them.