The real world isn't the same as a firing line at a shooting range. I read not long ago that treating every firearm as though it is loaded works great until in your mind you think the gun IS empty but it isn't. Perhaps you didn't follow a thorough check to see if the gun is unloaded. You may have racked the slide and no cartridge or shell came out but you didn't drop the magazine first before racking the slide to check if it was empty. Because you didn't drop the magazine first then you might have just put a loaded round into chamber. But in your mind you think the gun is empty now. You pull the trigger thinking the gun is empty and safe then BOOM. Now you look around to see if anyone or thing was hit by your negligible firing off your gun. I think keeping your finger out of the trigger guard has got to be one of the most ignored safety rules. Next time you go to the range just watch those at the firing line. Notice how many actually have their finger in the trigger guard. As a shooter brings his gun up to on target level his finger should not be inside the trigger guard. I am willing to bet you will see quite not on target but their finger is on the trigger. Perhaps we all should even notice if we are in the habit of doing exactly that. As an example I have had single stage trigger revolvers that had basically hair triggers. Perhaps you take a shot then look at your target to see where you hit. You pull the hammer back for the next shot. Opps your finger is still inside the trigger guard and even on the trigger. As you move your hand raising or lowering the gun or even repositioning your gun in your hand coming up on target BOOOM the gun goes off. I have seen very experienced shooters that know the safety rules that this has happened to. I can just hear people saying only a stupid person has an ND. IMO Only a stupid person believes that. Accidental shootings can happen to anyone no matter if you think you can't have a moment of brain distraction or neglect. Watch this video to learn a little bit more about real life safety concerning the basic four safety rules.