I use to teach the CCW course here in LA, and naturally talked a good deal about gun safety.
One of the points I tried to make with each class was that probably the person most likely to have a Negligent Discharge were those who were totally ignorant about guns, and those who had handled them, used and generally been around them for a long time.
The first group because of lack of knowledge, and the second group because of that old saying (in the Navy, at least) "familiarity breeds contempt."
If you handle guns enough, over a long period of time, you're going to find yourself at some point in a situation where you have a loaded gun in your hand, but aren't consciously aware of it.
Which calls to mind something I saw as a "signature" on another forum: "it's not the things you don't know that are the most dangerous, it's the things you think you know, that simply aren't true, that are going to come back and bite you in the a**."
Never take gun safety for granted...but also recognize the limitations we humans share.
If you can ask: "how could anyone be so stupid?".....stand by!