Being Mean in most cases, but can be obtained by Being Nice as well
Angry Essences can be obtained from interactions with Sims. Being Mean is one obvious way to obtain these essences. However, some Sims drop Sad essences instead of Angry when being mean. If you do not want to be mean to any Sims, it is suggested to try being nice to Vic Vector, who drops Angry and Sad essences when Being Nice no matter your friendship level. It can also be obtained by Being Nice to Sims who you don't have a good or average relationship with. Strangely, Angry essences are Fun essences despite the fact that most fun sims are very nice.