Dragon Age: Origins
Actions taken in each of the origin stories affect NPC’s and quests when you return to the areas.
Several NPC’s will attack you until killed if you handle situations certain way, including a possessed child.
Certain party members will turn on you and attack if they don’t like you enough.
The big bad man since the beginning of the main story will join your party late in the game, but early enough for it to matter, in exchange for losing your original companion.