A few years back, was hunting at the Grandma's house, last day there, went with some of the little ones to shoot the Marlin 60's. Had a good time explaining safety, teaching some technique, and more safety. Shot a few mags, tubular mags, after the bolt locked on the last round, I dropped all the way the racked it again. Pack up and go home, few hours drive, get home and I'm cleaning guns right after we get done unpacking. Then I take out the one of the 60's and rack the bolt and a .22 round falls out, rack it again and again, and there's five rounds at my feet. I'd had taken it for granted that the 'last' round was the last round, when in fact, the weapon fail to feed, I think its empty, drop the bolt, rack it again to make sure its empty, as if that's good enough or even made sense, and unintentionally loaded another round in the chamber. Lesson learned, I remove every mag to verify if its loaded or not, always look for the orange pusher on 60's and shotguns, and rack every action at least three times on a gun before storage.
I've made safety part of the fun while shooting now, and tell every little one or any inexperienced shoot I take to the range to, 'slow down.' Because if you have a problem you'll naturally what to fix it, but you don't know how. So you'll start pressing buttons, racking things, and dropping mags. All the while you've forgotten the basic safety rules and are going to town trying to fix the gun, you get frustrated and stop thinking about you actions and you surroundings. Take it easy, stop, put your safety on, set the weapon down or hold it in a safe direction if we're in the field, and come get me. I never rush new shooters at the range on anything, I do things on their time. If I take someone to the range, or the field, I take their safety as my personal responsibility.