So the joke goes (thanks, CC!)...
The GI wakes up in a hospital room. The nurse fetches the doctor who explains to him, "You were blown up in an ambush. You lost your right hand and arm. You're lucky -- we replaced it with a Bionic with super-human strength. Be careful though -- it's voice-controlled, but we haven't worked out all the bugs -- it takes commands literally. Again, be careful!"
The troop says, "Thanks, doc," and ponders the possibilities. He finds he can throw hand grenades like an M203, and lift a Ma Deuce effortlessly -- but his gross motor movements are choppy, like a big-dog puppy.
He gets into the shower and thinks, "Hey, I think I'll rub one out." As he soaps up a chub he commands, "Jerk off."
To his shock and horror the hand yanks his gear clean off. "OWW! F@CK ME!" at which point his arm rams his junk into a sensitive area.
"OH, DAMN! WILL YOU LOOK AT THIS $HIT?!" at which point he gets stuck in the eye.
(Sorry for the visual
)