Your colony is, above all, made up of people — living, working, hoping for the future, and depending on your decisions. Monitor their condition and take into account how they react to your choices. Overpopulation, food shortages, or supply disruptions can quickly lead to declining efficiency, crisis, and riots.
The population achievements are numbered — the first colonist awake, then 200, then 500, then every house filled. Housing is therefore a real capacity limit, and the Modular Housing structure from the Day One changelog is part of how you raise that ceiling. Living areas have to expand in step with production, or you will hit the wall literally before you hit the wall metaphorically.
Morale is a named, displayed stat — the demo patch explicitly adjusted the Morale bar display — and the state of your population determines the performance of the entire colony: its productivity and its ability to endure prolonged periods of danger. A strong and well-supported society recovers faster from attacks and moves forward with more confidence. Recovering faster means morale compounds; it is not a cosmetic mood bar.
Two achievements describe the social contract: Keep Promises and Restore Trust. Trust can be lost and then recovered, which means the game models it as a damage-and-repair stat rather than a permanent state. You make promises to settlers, and whether you keep them is tracked.
Food shortages are named as a direct trigger for declining efficiency, crisis and riots. The Canteen is the building that turns food into morale: the Day One Update fixed a bug where the Canteen was not receiving production bonuses properly. A canteen that works is the difference between a hungry crowd and a fed one, and the population system punishes the difference.
Overpopulation is listed separately from food shortages, which implies density itself has a cost — not just a headcount cap. Combined with the emergency events (accidents, disasters, environmental hazards such as acid rain) that disrupt operations and trigger cascading problems, the colony has several independent ways to spiral, and each one hits productivity, which hits your ability to fix the others.