Herro all,
I don't have a lot of experience with DF yet, so I generated a disgustingly peacefull world in which to learn. After several miserable attempts and hours spent reading the wiki, I had a fort survive long enough to notice the dorfs would stagger about and leave trails of vomit every time they went outside to get some more wood. There's already thousands of units inside Urist, why are you going outside for more? So I read up on Cave Adaptation on the wiki. According to that, any sunlit tile (any tile that has ever been exposed to sunlight) will trigger a cave adapted response (dizziness and nausea) and reduce the amount of cave adaption by a tiny amount. I don't want the military too busy staggering and hurking to fight, so I built a new barracks above ground, roofed it over, set them to sparring in their new digs, and forgot about it. A couple years later the first real threat shows up in the form of a dragon. Concerned he would burn down my wooden fort if I just slammed the gate, I sent the militarey out to deal with him. As soon as they walked outside, they set to spewing and staggering like college freshmen. Uh, what? They've been above ground for years except for the times they go to eat or sleep, how are they cave adapted?
In case you were worried, one of the little bile fountains lopped the dragon's head off with a single strike and I spent the next six months of game time listening to Urist whine about not being let outside to bring in the flaming wood as my bone carver made *Dragon Bone* jewelry.