Group dynamics involves how people interact and behave in groups. There are different types of groups like primary groups of close friends and family, secondary groups like organizations, and planned groups formed for a purpose. Groups go through stages of forming, storming, norming, performing, and adjourning. Groups are effective when they balance task functions like decision making with maintenance functions like building relationships and addressing members' personal needs. Groups can benefit members but also have risks like oppressing some and creating conflicts.