While most of us will strive to give our Sims positive Emotions to improve their performance, negative Emotions happen. They can also be negative and limit the things a Sim can do, such as when Uncomfortable and needing sleep.
Emotions can boost Sims' performance in Skills, Careers, Social, and Romantic Interactions. The Sims 4 brings with it the Emotions system. The Sims 4 Emotions Emotion System Mechanics, Moods, and How to get Sims Feeling Each Learn all you need to know about Emotions in this Guide
