I once had a squad of seven marksdwarves. They were all still green, as they were the first batch of military that weren't wrestlers at the time. My champion wrestlers had been slain in a goblin siege [somehow], so the marksdwarves were all that was left.
So, here we are, they're shooting at targets, when "An ambush! Curse them!" appears. I go, "No problem" and send them out to deal with it. About eight seconds later I noticed that the gobbos outnumbered them nearly three to one, and that it couldn't possibly end well. As it turned out, they filled the little jerks with wooden bolts and won and survived, but not without sustaining heavy injuries. So, per the 40d medical system, they were laid in their rooms to rest.
Fast forward a few months. Booze shortage! I had forgotten to make any, and had no natural water. Apparently, giving the invalids a drink was pretty low on their priority list. So, within a game week of my noticing, all seven marksdwarves go insane from a combination of drowsiness, dehydration, and unhappiness. By some odd sort of luck, six out of the seven went stark raving mad, while the last threw himself into my magma moat. So, I had six batshit dwarves running amok, pulling levers, and generally harassing the hell out of everyone. Their antics eventually caused a tantrum spiral that later doomed the entire fort; it's just as well, because they somehow managed to mess up my magma delivery system and flooded most of the lower levels with magma.
My favorite part was how they occasionally tried to regain a semblance of their old lives by going to the archery range, only canceling the task due to being "too insane."