Happiness is an important thing to think about when planning your town. It is rated out of 100 and this can be checked by mousing over a Civilian in the Citizens panel, or by right clicking civilian on main screen. Mousing over the citizens panel icon gives average happiness value for all population, as well as the target happiness required for a new influx of immigrants.
Happiness is important for one thing currently: attracting new immigrants. The higher the happiness, the more quickly you will attract more immigrants (so long as you have spare Personal Rooms!). The target happiness value required to bring in new citizens is twice the current population, up to the point of 40 population. From that point onward the requirement for getting immigrants is always 80 happiness. When immigrants arrive, the average happiness drops substantially, and must be raised again in order to attract more immigrants.
Workload. How it works, more or less.
Happiness is affected by many factors, but currently the most important is workload. It's virtually impossible to maintain happiness if all townies are working nonstop, or even all idling without any work to do.
A bit of explanation on how it works: First, it is a bit of a change of the old system which was idle equals happiness, and is a bit harder to manage(but not too hard once you set up to work with it.)
Townies now have two new invisible stats, a work counter and a idle counter. As a townie works, (Tilling, harvesting, mining, etc.) their work counter goes down, and their idle counter goes up. As a townie 'idles' (sleeping, eating, and standing around), his idle counter goes down and his work counter goes up.
If either counter is at 0, the citizens will begin to lose happiness, at a rate of -1 each 60 turns (-48 each day). Consider 0 to mean the townie is overworked or bored.
Townies do not receive any happiness bonuses from decorations in line of sight if their work or idle counter is at 0 (losing happiness), but Townies do not lose happiness when sleeping, even if the counters are at 0.
If you overwork your citizens, they begin to grow unhappy, and if you leave them be doing nothing for prolonged amounts of time, they also get unhappy. To keep your happiness high, you might want to work out a system that allows some to work and some to idle, and then switch it around.
Decoration Happiness Boosts
If not overworked or bored, every 120 turns a townie will check its line of sight for any decorations with happiness modifiers. Then, they will register one random modifier and increase or decrease their happiness rating accordingly. They will detect these in their line of sight even if they're sleeping.
With easily accessible <happiness>2</happiness> decorations (flowers, bonsai, harps and architect tables) it is possible to fully cover town space and achieve theoretical gain of 48 happiness per day.
Even higher quality decorations available with <happiness>3</happiness> modifier and one (Bird in golden cage) with <happiness>4</happiness>, these are good for installing in area where townies concentrate.
Set up idlers zone - market or balcony with high quality decorations and keep eye on it: no idlers, means your townies are overworked and losing happiness, too many idlers - add more jobs.
Decoration placement. Only one decoration counts, so with townie minimal LOS=3 they can be placed 6 tiles apart. It's unwise to place decorations with different values, like bird cage and candles, together, candles will steal happiness ticks from cage. Also, remember: walls and pits break LOS.
Finally, there are items with negative happiness - dead bodies, stink clouds, and all other things you wouldn't want near your house - do not stockpile them in the middle of the your town or in a building.
Other happiness increasing mechanics
Sleeping on bed adds 5 happiness, and eating while sitting on chair add 4 happiness.
Eating food adds 1d2 happiness. Each food type has a 16400 turn cooldown, or 5.7 days of cooldown, promoting variety in the food you feed your citizens. Eating Cake add 2d5+2 and it also has 16400 turns of cooldown.
Fishing adds happiness because fishing set is a trap, that gives 1d3 happiness to a citizen who steps or stands on it. Traps have 223 turns cooldown, but the effect doesn't, so multiple traps can be activated in a row by townie running somewhere else.
Other happiness decreasing mechanics
Townies lose 5 happiness each 120 turns if they are starving. Going to get available food does not count as starving, even if food is far away.
Performing other task (sleeping) counts as starving even if food is available.
When new townies migrate, they reduce happiness for all townies by fixed percentage.
- 2 migrant - 65% happiness left.
- 3 migrant - 50% happiness left.
- 4 migrant - 40% happiness left.
Guard and happiness
Most mechanics, listed above, do not work on guards, but migrant's decrease does, so their happiness is, usually, low.
Guards excluded from average happiness calculation, and do not affect migration.
You can boost average happiness to get next migration wave by temporary making unhappy members of community into guards, average happiness will be updated when you unpause the game or save/load.
Harassment due to supervising Soldiers supposed to decrease happiness, but it's currently hard to tell how it works.
Planned but not working currently
Equipped hats supposed to increase happiness.
Table in Dining Room supposed supposed to increase happiness.