So for the longest time, I had a lot of idle dwarves. I was not the most brilliant manager, but I figured that I might as well let them party and drink their lives away. At least they'll make friends, have a good time, and grind social skills.
So all was well and good, random dwarven polls showed that everyone was ecstatic most of the time. Just about everyone was friends with everyone. Then one day, there was a tragic accident which killed 5 dwarves in one fell swoop, I think 2 children and 3 soldiers. It might have killed them while they slept, I'm not sure. Whatever. I also think I lost a couple more shortly afterwards through terrible injuries as a direct result.
So naturally, everyone was depressed. I should think they have every right to be. Tantrums were plentiful, and every so often a dwarf would go crazy or something, but it was a mature fortress and I didn't mind losing a couple of citizens. I thought things would pass.
Things didn't. Slowly, I realized that thanks to the intricate friends network I had unwittingly allowed to form, the suicides as a result of the original accident were causing more tantrums and suicides. At this point, my entire industry had stopped. Very little was being made, and dwarves rioted in the halls freely as the body count slowly but steadily rose. I couldn't even make enough coffins fast enough. My fortress was spiraling out of control. In one afternoon, my population had gone from about 200 to 130. Without some sort of mass sedation, all my dwarves would be victims of their own emotions.
I wasn't willing to let my beloved fortress bleed itself to death, and I figured if I was only going to have a couple odd dwarves in the end I might as well start a new fortress. Truth be told, things hadn't been terribly exciting before this fiasco. I flooded the lower levels with magma and abandoned the unfortunate place.
What could I have done? What do you do when this happens? I will try and keep my dwarves from making too many friends in the future, but surely there is some way to recover the situation. I tried to reopen my statue garden, but the few parties could not distract my poor dwarves from the turmoil for long.