In your opinion, what was the best map gimmick in Fates, and what was the worst? Which was the most interesting, and which was the most irritating?
In my opinion, the best was the wind currents that slowed down flying units in chapters 11 and 24 of Birthright, and the worst would be a tie between the giant streams of fire in Birthright chapter 23, and the winds in Conquest Chapter 20 (those winds would have been a lot better if only one or two at a time and they didn't push you as far).
Note: This includes but is not limited to Dragon Veins (example; the fox illusions in Conquest Chapter 19 count as a map gimmick)
EDIT: I don't consider it the best or the worst, but the water draining in Conquest chapter 10 gets an honourable mention.