For me it was self-exploration and exploring the fringes of my identity using psychedelics and other drugs that my parents didn't particularly approve of. For s

For me it was self-exploration and exploring the fringes of my identity using psychedelics and other drugs that my parents didn't particularly approve of. For some of my friends it was sexual identity (which was much more taboo than today). In general I think "rebellion" is the consequence of becoming a fully aware individual capable of independence from parents. Parents want to exert control over their teens, teens want to have agency over their lives, and the conflict between those two positions is framed as "rebellion".