One day, after a regular live-ammo mortar practice, the mechanized infantry company was sent out on the shooting range to collect shell fragments and other non-biodegradable debris. The standard procedure was that the soldiers worked in pairs, with both of them putting the collected debris in the other guy's backpack to save time.
It so happened that one of the guys found a clean, unexploded mortar shell. Being in the infantry, he should have remembered the correct procedure for dealing with duds. However, he didn't. Nor did he possess the common knowledge to exercise the appropriate care when dealing with 2.5 kg high explosives that was meant to go "BOOM" upon impact some 45 minutes ago. No, this guy simply picks up the shell, goes over to his buddy and drops it - detonator end first - in his backpack.
Miraculously, the shell didn't explode. The "dumber-than-the-average-loaf-of-bread"
soldier was never sent on shooting-range cleanup duty again, but he is most
probably still alive to ruin the human gene pool. When inquired upon for his
purpose of dropping a live mortar shell into his comrade's backpack, he replied
"we shouldn't leave duds out there on the shooting range, should we?"