Four Brahmaviharas
Also known as Four Immeasurables, Four Infinite Minds (四無量心).
A set of four virtues in Buddhism. It’s similar to the four cardinal virtues in Christianity and Stoicism but more relational and interpersonal in nature.
Loving-kindness (metta/maitri) - having good intentions towards all. A common practice is the metta meditation where you attempt to expand your circle of loving-kindness, beginning with the self and gradually extending to family, friends, strangers, even enemies.
Care (karuna) - acting out of compassion for others to relieve their suffering. Fun fact: the term is related to karma (action) which conveys the element of action is this virtues. It’s not only just having a feeling of sympathy to the sufferer but also extending help to them too.
Freudenfreude or sympathetic/vicarious joy (mudita) - taking genuine pleasure in the well-being of others. Probably the reason why some Buddhists proclaim Sadhu three times as an expression of praise, rejoice and gratitude.
Non-egocentricity (upekkha/upeksa) - even, impartial attitude towards all. This involves moving away from the self-centred egoistic mindset, where we treat people based on their relationship with us and forming in-groups and out-groups as a result.
Easy to understand, difficult to follow.