Pretty much every Zelda: Breath of the Wild player has come across Tarrey Town: a little community you can grow through some NPC errands. Did you finish building it? Because it's one of the best examples of a low key worldbuilding quest that Breath of the Wild has to offer. As it turns out, there was more than meets the eye to the whole Tarrey Town scenario.
As Reddit user justlookingfordragon points out, the map actually changes as you progress through the Tarrey Town questline. Even small little moments like Hudson (the first real resident) arriving changes the map, and as each citizen moves in, it alters itself just a tiny bit. It's something you'd never realize was happening until you actually sat down and thought about it in this highly analytic era of the game.
The Tarrey Town revelation joins a long line of "years later how did I not realize this" moments, including the Sand Seals trick.