My favorite was possibly when I first discovered the danger room. I trained up a couple of elite armored squads, wielding copper and iron. One squad of copper-clad sworddwarves, one of iron-clad axedwarves.
The axedwarves made up the police force. Beatings in this fort meant Swift decapitation.
Well, I began to notice how my nice, legendary warriors ran at least twice as fast as all the other lazier dwarves. And it was taking a little while to move some things from stockpile to stockpile. I got bored with them lazy peasants.
So I hatched a brilliant plan. Why not stick all the peasants in the danger room unarmored?
I stuck in about ten. about half of them died of exhaustion. the other half became great warriors, and strong too. I was beginning to like my power.
I stuck all of the peasants in the fort in.
...
...
You have a good half of the haulers dead, the rest are terribly upset at my cruelty. They begin to revolt. My legendary axe-wielders make certain to kill everyone who dares throw a tantrum.
In the end of it, I have an only slightly reduced military (all due to tantrums and subsequent beatings), and I don't mind that much, because the survivors are now extremely mentally fortified.
But I have about two psychopathic peasants left.
And then a few babblers
And an emo
And a slightly undersized catacombs.