Let's say you chase the Garleans out of an area, and then you go into a town that's been utterly trashed. There's two NPCs who are both looked to as leaders, but they have different ideas on how to rebuild the town, and turn to you to break the tie. One wants to wants to use abandoned Garlean magitek armor to move construction materials, and to salvage the materials from the now-abandoned Castrum nearby, because it will be the most expedient way. The other argues that people saw too many of their fellow villagers die at Garlean hands, and bringing magitek into the town and rebuilding everything out of salvaged Garlean steel and cermet would just be rubbing salt in the wounds.
If you choose the first one, it opens up quests where you go into the Castrum and collect materials, hijack magitek armor, etc. If you choose the second, it opens up quests where you go help get local materials, help rebuild the buildings in the style they were before the attack, etc. At the end, the look of the village and the incidental dialogue from NPCs could be different; in one case you have a village built of metal, and in the other more familiar Eorzean designs. But in the end, the village is rebuilt either way, and when you leave the village and move on, it never comes up again in the story.