OK, so firstly: Far Cry 3 spoilers ahead. Like, game-ruining spoilers. Don’t say I didn’t warn you.
You’ve changed, man
Character development is a weird thing. Watching a character change and grow over the course of a story can be a fundamental to a satisfying narrative arc; the immature rich kid becomes a principled man, the girl from the streets flowers into a strong, confident woman who doesn’t need to smoke, and so on.
There are plenty of books and films that gift/curse their characters with interesting (and sometimes even profound) changes, but far fewer games that do it with any success. I think that this is partly due to a lower standard of writing in games in general, but I think it’s also much harder to write believable character development into a story when the character is controlled by a player, ie you. Unless the story and characters are written well enough for the player to relate to them, the player herself experiences nothing of the change portrayed on screen.