If there's one thing I can't stand, it's when people put things back (specifically, movies or games) in the wrong case.
If there's one thing worse than that, it's discovering that I've done it.
Open up the Trauma Center: Under The Knife case, and discover Final Fantasy III. Pop open Final Fantasy III's case, and it, of course, contains Animal Crossing: Wild World. So what did Animal Crossing: Wild World contain? Well... nothing.
So now all the games are back in their proper cases, and Trauma Center: Under The Knife remains safely in the DS.
Which is probably in the Gameboy Advance container. ;)