I had a friend years ago that started to do his own gunsmithing on customizing 1911's. He started with doing trigger work and he would regularly have his newest creations in his car and want to show them off the first opportunity he had.
I should mention a couple of things here. We were really good friends, known each other for years, both did IT work, and we both worked for the same company at the same location. The company had a 'no guns' policy period, pretty sure that extended to the parking lot too, but we didn't usually care about that as we would go shoot after work and we would leave our firearms in the trunk unloaded.
He was one of the safest people I had ever seen around firearms. Shot with him for years and years.
Fast forward to one day he made the final and perfect modification to one of his 1911 triggers. Keep in mind this is probably the 20th mod he wanted me to check out
Around lunchtime at work, we went out to his car, he was in the driver seat I was in the passenger seat, he handed me a the 1911 and said try the trigger in that one, all proud etc. (this was normally how he showed me his trigger mods, we did this a lot)
We were in a sedan so at some point, even if just for an instant, I know the muzzle was pointed at something I didn't want shot. as soon as I got it, I kept it pointed at the floor between my legs like I always do.
Then me being me, pulled the slide back and a round popped out.
I lost it on him, bad, left the gun locked back on the passenger floor of his car, got out of the car and left. I needed some time to calm down. Didn't go shoot with him that night.
I have a ritual when anyone hands me a pistol like that, drop the mag (confirm no mag), finger out of the trigger guard, pull the slide back 3 times in the safest direction possible (in a car, that is the floor even though I do not want to shoot the floorboard)
This was so out of character for this friend. Very dependable reliable trust your life to sort of person, he just made a mistake. It could happen to anyone. I continue my ritual even if it only ever saved me from something one time in decades, that one time was worth all the slide racks.