Easy ways to avoid tantrum spirals:
- Masterwork prepared roasts
- Legendary dining room (11x11 smoothed room with tables/chairs is usually enough)
- Soap bars and a well
Individual bedrooms by the end of year 2-3 is important. An 11x11 area can easily be chopped up into 16 bedrooms, with doors in the corners between each bedroom. If you are short on doors, you can do it with only six doors for the sixteen bedrooms, but the more doors you have in corners, the more path-friendly the area is.
Layout for 48 bedrooms in my latest fort. I did this across (4) levels for an eventual total of 192 bedrooms for the peons.
Once the rooms are dug out, smoothing them will turn them into very nice bedrooms. Place a single bed and cabinet/coffer in each, assign them to dwarves, and you'll get lots of good thoughts. They'll be happy for sleeping in their own nicely appointed bedroom, they will admire their bed, and admire their coffer/cabinet.
If they have pet cats or non-grazers, assigning those pets to their bedroom can help out a lot as well. They will get a good thought from being comforted by their pet (I think close proximity helps).
Depending on time constraints and how many you can spare for engraving duty, engraved bedrooms are even better and more likely to result in happy dwarves. Ecstatic dwarves are rather difficult to tantrum-spiral.
My current fort has gone from 21-25 population down to 4-6 survivors two years in a row now due to werepanda attacks. The survivors bucked up, cleaned up, isolated (walled in) the suspected infected, buried the dead, and no tantrums were had.