Happiness and Discontent
Happiness 
is a value tracked independently for each city. Cities gain or lose Happiness each year from various sources, and can also experience one-time increases or decreases. A loss of Happiness is called Discontent 
, so that changes are always positive numbers: it is either a gain of Happiness or a gain of Discontent .
A new city starts with a Discontent Level of 1. When the city accumulates enough Discontent (100 + 10*level) , it gains a new Discontent Level. Each Discontent Level increases city Maintenance 
and reduces Science 
by 5%. It also decreases the opinion of the city's family by 20.
When the city starts to gain Happiness instead, its Discontent Level goes down, eventually becoming a Happiness Level starting at level 1 and growing at the same rate as for Discontent Levels (100 + 10*level). Happiness Levels increase city Growth 
and reduces city Maintenance by 5% each.
Yearly changes to Happiness [edit]
- +2 in cities with Cathedral improvement with the Inconography law
- +1 in the cities of the Cleric family
- +2 for a governor with the Righteous trait
- +1 in all cities for a leader with the Righteous trait
- +2 for the Hagia Sophia wonder (requires Legendary culture)
- +1 for having at least one military unit from the city's family within its borders per wall, moat and tower
- +1 if your state religion is present in the city
- +2 / +1 per Pleased (opinion 100 to 199) / Friendly (opinion 200 or higher) religion present in the city
- +2 per Luxury sent to the city (+1 if it's a prefered Luxury for this city's family)
- +2 with the Monetary Reform law
- +2 with the Tolerance law per non-state religion in the city
- +1 for the Archive IV, Forum IV, or Treasury IV one-time projects (require Legendary culture)
- +1 / +2 for the Theater / Amphitheater improvements (Tier 2 /3 of the Odeon class improvements)
- +1 / +2 / +3 for the Cold / Warm / Heated Baths improvements
- +1 per Luxury sent to the city if your empire contains the Via Recta Souk legendary wonder
- +1 if the city is connected to the trade network
- Some event options add a Project that affects Happiness yearly
Yearly changes to Discontent [edit]
- +1 with the Slavery law
- +2 for a governor with the Debauched trait
- +1 in all cities for a Leader with the Debauched trait
- +2 / +1 per Angry (opinion -100 or lower) / Upset (opinion -1 to -99) religion present in the city
- +2 if the city was founded by a different empire
- +2 or more if the city has lost any amount of HP (caused by enemy attacks, fixable with the Repairs project)
- Difficulty modifier, from +3 at The Able up to +10 at The Great
- Some event options add a Project that affects Discontent yearly
One-time changes to Happiness and Discontent [edit]
- +20/+40/+60/+80 respectively for the repeatable projects Festival I/Festival II/Festival III/Festival IV (requires Weak/Developing/Strong/Legendary culture)
- +10 each time a city is attacked
- +??? for hurrying production, depending on the amount hurried [NEED EXACT VALUES], if you don't have the Monetary Reform law
- Some event options add Happiness or Discontent
- Some event options directly increase Happiness or Discontent Level