I actually remember some of my first few attempts from several years ago. One failed because I couldn't figure out how to change the z-levels (but a kitten adopted the butcher, aw, how cute). Another failed because I had absolutely no idea which of the dozens of workshops I should build with my limited initial resources. That was on a glacier/forest mixture with red sand.
Anyway, the first really interesting one was not so long ago. 5x5 embark (40d). Steep, 50 z-level-something Mountain in the middle. Flat forest in the northwest. River in the southeast. At the top of the mountain was a volcano opening.
For some braindead reasons, I thought that my first priority should be to get some water from the river towards the forest patch. So I started the plumbing semi-megaproject and ignored everyone but my two miners, who tunneled and channeled something through the bottom surface layer of the mountain. Yeah. No plant gathering, no farming plots, no brewing... the other 5 dwarves just sat there and waited faithfully that the miners finished their job. It must've been an "embark NOW" embark, because they survived actually quite well up until the water was almost at their position. Then, quite dramatically, I had my first and only tantrum spiral. I blamed the immigration wave of about 25 dwarves who had arrived just prior to the tantrum spiral, drinking all of the remaining booze and eating the last few pieces of meat, but obviously it was my fault as well for not actually doing anything with the 5 idlers from the start. Anyway, they got into a tantrum spiral.
That one was very remarkable, too. Not knowing what to do, I appointed a sheriff. He was quickly beaten to death by the mob. So was the major.
Pets were slaughtered, doors were bashed in, diplomats left unhappily, insane dwarves crawled with broken legs all over the forest clearing, fathers killed their wives infront of the eyes of their children.
The FPS dropped to something really amazingly low, like 1 frame/minute.
In the end, only the leaders of the mob, and an insanely skilled at social skills child survived. All of them had quite high bounties on their head for murder, assault and demolition. And they became the new leaders of this fortress.
Some more immigrants arrived, quickly fitted into this society of hard-nosed criminals, and the fortress became stable.
... until the goblins arrived later on and I got fed up because of them.