Needs

Your sim has needs. Needs are the reflections to the quality of welldoing. You need to pay attention to them in order to lead a happy, well-being sim.

Need failure
Be careful! If a sim's needs get low, the sim will face negative moodlets. You need to take the correct action to prevent something called a "need failure". First, when a need is in the red, The sim will start to complain about it. And if you continue to let the needs drop to grey, The sim will begin to rush to the right object to fulfill her needs, but if a sim doesn't make it within an in-game hour, It will be a need failure.

Need levels
31%+: Green: Need bulb is static

16-30%: Yellow: Need bulb bounces once a second

8-15%: Orange: Need icon begins to flash yellow at the same rate as the bulb

1-7%: Red: Need bulb and icon bounce twice a second. Sim starts to complain.

0%: Black: Need bulb and icon bounce 4 times a second. Sim starts rushing to the right object to fulfill her need. Otherwise, need failure starts.