The first thing I did when I got home from Fantastic Fest was buy Grand Theft Auto V. The game is amazing - overwhelming, but amazing. I'm only about 25% through Story Mode, but I've totally fallen in love with the story (and with Trevor, one of the all-time great sociopath characters in fiction). What makes the game so incredible is the sense of depth; everywhere you look everything has been thought out. Nothing feels like it's been randomly placed by a game engine. Every corner of Los Santos and the surrounding counties feels DESIGNED.
That extends into the little bits of character and dialogue. The video above showcases one specific example; the player takes the character of Franklin to the home of another playable character, Michael, and - in true GTA style - starts firing rockets at it. It turns out the developers at Rockstar saw this possibility arising, and prepared for it.