Two instances that really stick in my mind...
When I owned my first gun I had a click when there should have been a boom. I must have loaded 9 rounds instead of the 10 rounds the gun is able to hold.
When the click came I almost panicked...my first gun and my first range trip and I have potentially dangerous squib load.
I waited out the the 30 seconds as advised on the box of ammo by about 5 minutes...nothing.
So I ever so gently pull the slide back to discover that the chamber was empty and the slide lock failed to engage.
This is the only time this gun did this to me.
Just one of those things I guess.
Next is the time that I first owned a 1911.
It was a Llama double stack Para Ordnance clone (series 80). Very rare. I still miss that one...
It was loaded and I pulled the trigger on the half cock to release the hammer and the hammer slipped from under my thumb.
The Hammer made a quick and powerful "thwack" on the firing pin.
The gun did not go off...much to my relief...but, when I dropped the mag and ejected the round I saw on very deep pit in the primer.
When I took the round to the range it went off as expected... thank god it wasn't ignited at the wrong time in the wrong place. An Officer's model .45 going off in a small apartment living room would have surely gotten me much more attention than I would have wanted.
The only damage I would have done with that round is some rug and concrete damage in a rental unit (the four rules are your friends), but it certainly instilled a new found respect for guns that I will never forget.