The Bad Mood glitch is a bug in Late Night update, The Sims 3 Outdoor Living, The Sims 3 Generations and The Sims 3 Town Life that effects a Sim's mood.
This glitch only occurs on Windows and Mac OS X and is not present on The Sims 3 for Consoles and The Sims Medieval. The Sims 3 Late Night does not have this glitch nor does Fast Lane and prior but it will occur if the Late Night update is installed.
Info about the glitchEdit
This glitch causes a Sim to be in a bad mood despite not having negative moodlets. It is caused by the Well Rested Moodlet and the Nectar Machine. The value of the mood will be -100.
This bug was first mentioned on a gamefaqs thread where the well rested moodlet was incorrectly stacking negative or positive moods.
It is also believed that a similar effect will also have a Sim in a very Good Mood.
This occurs with the Well Rested Moodlet is it is +20 or lower; using cheaper beds will cause this. Making nectar on the basement also can cause this glitch.
In addition, it can cause the following effects. The other effects of the glitch are:
- Sim will not help with Homework.
- The player is not allowed to choose the Work Hard option at Work and School.
- The Mood score is lower than usual. In addition, the Mood score for Job Performance and School performance is lower than usual.
- Some actions by be dimmed and cause the "Mood too low!" message when the player tries to use some actions.
- The Sims constantly frowns in the UI.
This glitch set a Sim's neutral mood value to a negative number (-100) instead of a value of zero. This causes a Sim to be in a bad mood even if the Sim has no negative moodlets. Saving and then reloading the game will reset the value to zero (Normal value).
Because of a miscalculation of the Well Rested Moodlet, it would incorrectly set the Mood to a negative value causing a Sim to be in a Bad Mood regardless of moodlets. 
Methods of the glitchEdit
Well Rested methodEdit
This is caused by having a cheaper bed and sleeping on it. If the player lets the Sim sleep until they are Well Rested, the Sim will have the glitched Well Rested Moodlet that appears to give a mood boost as it is a positive moodlet. Later when the moodlet expires, the Sim will be in a bad mood. This occurs regardless if the Sim has any negative moodlets. This first appeared in Late Night via the 6.1 update but the glitch will occur even if the game's version is Fast Lane or earlier.
If the energy is filled but does not cause Well Rested such as Vampires having a vampire slumber or using the Moodlet Manager, the glitch will not occur.
This method only works in Late Night (6.1 update) through Generations but method of the glitch appears to be fixed in The Sims 3 Town Life (1.24).
It is also believed that the Sim will also stay in a Good Mood if Well Rested is +30.
This will occur in games updated to 1.18/2.13/3.9/4.6/5.4/6.1 even if The Sims 3 Fast Lane, Ambitions, High-End Loft Stuff/Design & High-Tech Stuff, World Adventures, The Sims 3 Deluxe or The Sims 3 is the latest version installed.
This method appears to be fixed as of The Sims 3 Generations.
This method requires World Adventures to be installed to have the nectar maker.
When a Sim makes nectar with the object, the Sim will be in a bad mood even if the Sim has no negative moodlets. Unlike the Well Rested method, this glitch is still present in The Sims 3 Town Life as seen in the image.
Workarounds and preventionEdit
There are ways to fix this. The first 3 are EA supported but the 4th is a mod that fixes the glitch.
- Save the game and reload the game to reset the Mood.
- Use testingcheatsenabled to remove the Well Rested Moodlet (If +20 or lower) and then save the game and reload. Use method 1 if the Sim is a Bad Mood after reloading.
- Cancel the Sleep Interaction to prevent the moodlet from occurring.
- Use this Mod from Mod The Sims. (This mod will fix the glitch but it is not officially supported by EA.) However, this glitch (At least for Well Rested) has already been fixed in later versions.