Mood

A Sim's mood is determined by the level of needs they have. There is a bar next to the needs that indicates mood. Green (which is usually indicated by the upper part of the bar) indicates good mood, and means that the average need level of the needs are green. The higher and greater the amount of the green, the better mood the Sim is in. If there is no color in the bar, then it indicates that the Sim is in a neutral mood; neither good nor bad. Red (which is indicated by the lower part of the bar) indicates bad mood, and means that the average need level of the needs are red or yellow. The higher and greater the amount of the red, the worse mood the Sim is in.

Sims that are in a bad mood will only do things that will increase their need levels (such as sleeping when energy is low, eating when hunger is low, etc.) They will not do anything that will either have no effect or worsen their moods (such as study, exercising, etc). Sims in a good mood will be able to do anything.

In the Sims 3, mood is controlled by Moodlets the sims have.