The stories of defeat are the best, i got bored of my settlement because it never died.
It takes some practice to balance your fort between "impenetrable" and "reckless", but once you reach it, !FUN! almost never stops.
My fortress just went down from 120 citizens + over 70 guests to maybe 25 dwarves because a forgotten beast in a shape of an elephant, composed entirely of flame, wrecked it's way into my living quaters and unleashed fiery inferno causing utter tantrum, and it was only stopped when some lucky marksdwarves finally put a couple bolts into it.
Right after that, I had a goblin siege show up, and my militia took turns letting them in by opening the gate and slaughtering a few, untill the gate jammed and I had maybe 40 goblins pour in, which massacred what was left of my militia, save for one hammerdwarf who went into a martial trance and broke hundreds of bones in his flurry of strikes. After that fight, the siege was lifted.
LITERALLY A FEW IN-GAME DAYS AFTER THAT, a venomous fucking-something with wings and a shell came out of the caverns, another forgotten beast, and flew right into my quaters - I managed to hide the entire population in my weapon stockpile level above that and drafted every dwarf, letting them charge the flying turtle-bee. The attack was led by my captain of the guard, who was armed only in his shield, his steel axe and a silk robe - no armor, he was naked (Which caused a few dwarves to feel uneasy) - they overwhelmed the beast, with help from a few war dogs that were passing by.
My best fortress thus far.
