Trading with elves, and I somehow amassed an enormous supply of obsidian which, after covering my nobles' rooms with, I made into swords and tried to sell about a million of them to the elves. "Little did he know" obsidian swords are the ONLY non-wood weapon made using wood. At least they haven't declared war on me... yet. They did leave rather huffily, though.
Also, my current fortress area thinks good things are better in twos. Whenever I get a goblin ambush, I get another goblin ambush literally seconds later, to the point I was convinced this was a feature until I learned it wasn't. Okay, no big deal, just set lots of cage traps and put them in the stripper cages.
But when the same principle applies to forgotten beasts who exhale noxious fumes? Fun ensues. And the facepalm factor comes into play after I had walled off so I could be invincible temporarily hold them at bay until I was ready and then immediately dug a tunnel out for diverting the cavern lake into my underground shroom farm, allowing them to just waltz in through the water main. They both struck probably within five minutes of each other. Fortunately, my mighty dwarf militia killed them off with only about 8 deaths total.
Oh, and checking the justice screen and seeing the people being beaten and caged were being punished for vandalism or fist fights, and my Captain of the Guard had a massive jail time racked up for 5 or 6 murders (I'm sure it had nothing to do with beating people with an obsidian sword). Nobility at it's best.