On the theme of strange body location-related things, my personal favourite was trying to do headshots on Oblivion with a bow.
Apparently, heads in Cyrodil are in a state of quantum flux, and your arrow just goes sailing through them.
Like Shroedinger's Swede.
My favourite recent schwat the fuck though, was playing Dragon Age.
Having just spent the last 80 hours of gameplay romancing Zevran, I get to the final assault on Fort Drakon, we have our tearful goodbyes etc etc, and then he says something along the lines of "Ah, my friend, I would attack the Black City itself by your side"
FRIEND?
I just saved your life repeatedly, I gave you purpose, I gave you some spiffing boots and gloves, I humped you in between every mission and taught you how to love.
And now we're friends?
Considering the high standard of the dialogue in Dragon Age, I spent the rest of the final mission yelling "FRIENDS?!?!".