I have several, all from basic training (US Army) and all from the same young lady.
The first two come from a portion of training wherein you are exptected to demonstrate you have properly learned several key skills in the previous weeks. The first was simply placing an M18 Claymore mine. For those who are unaware, on the front of the weapon written in very large embossed lettering is the simple phrase "FRONT TOWARDS ENEMY". I had long wondered just who was stupid enough to need the hint that the most dangrous potion of the weapon ought to be pointed at the people you wanted to kill.
The process for arming a claymore is pretty simple. You simply stick the mine into the ground facing the proper direction, insert the blasting cap and detonation wire, unroll the wire to a safe firing point (the lethal radius of the weapon is >75m to the back, >200m to the front), attach the M57 firing device, and then activate.
Upon my (successful) completion, the drill sergeant turned to this young lady and congratulated her. During his pause she was literally beaming with pride until he continued "Because you just killed yourself". Apparently, she thought she needed to be able to read the "FRONT TOWARDS ENEMY" because clearly this would be written on the back (how else could she remind herself which way was the front).
The second came with a demonstration of our ability to prep and fire an AT-4 (a disposable, light anti-armor weapon). The process has only a handful of steps - pull down a strap and attach it properly (so when you fire the tube doesn't just fly off your shoulder), flip up the sighting apparatus, cock the weapon and then press the fire switch once a target has been acquired.
The best part is, the AT-4 has directions printed on the sides. And, just in case the user cannot read (or cannot read English at any rate) the directions are printed in picture form. When holding the weapon you can see the graphic for the entire process. In spite of this, or the fact that there were people on either side of her doing it properly, this young lady cocked, fired, then deployed the shoulder strap and sight.
The last, and most incredible, came when we were learning how to properly load an M-249. For most here, the basic process is relatively simple. You open the feed tray, load the first round at the proper point in the the feed tray such that the belt is entering through the left side of the weapon, close the tray, and cock the weapon. At this point it is ready to fire.
I can understand loading the weapon from the wrong side. It would fire once, and then the belt would fall to the ground, but at least it would function. I would even understand loading the rounds backwards because at least the feed tray was closed. What she was trying to do was so mind boggling that I'm not sure simple words can describe it.
She was holding the belt of (thankfully dummy) ammunition such that the base of the round (where the primer is) was resting upon the feed tray (and the tip of the round, the actual bullet was pointing into the air). She then had the belt running such that the first round was near the barrel and the last was near the stock of the weapon. Because of the precarious postion, she was HOLDING the rounds in place while trying to slam the feed tray closed. Should she succeed at overpowering the structural strength of the rounds, she would succeed in crushing her hand as well.
To put it another way, imagine a 3D axis. the belt OUGHT to point (bullet side) down the positive x-axis and proceed from an arbitrary point on the positive y-axis to the origin (the negative y-axis is where the shells are ejected). She had the bullets pointing down the positive z-axis with the belt running from an arbitrary point on the negative x-axis to the origin.