@MrsFlynn --- Thanks for the link. It seems that the Moodlet Manager is even more powerful than Moodlet Solver in TS4 because Sims can use it for good or bad --- zap, it seems zaps memory and Sims don't like it --- on other Sims.
To use it for good, it seems that if a Sim needs to get rid of their negative moodlets, then, another Sim needs to push the cure button on the Moodlet Manager.
In TS4, Moodlet Solver simply rids the Sim who drinks it of negative moodlets.