Reincarnation cycles occur because we desire to evolve spiritually. This Law ensures appropriate Karma is resolved and Dharma fulfilled, whether in a single lifetime or subsequent lifetimes. The Collective Spirit does not bestow suffering upon anyone during these physical lives, as the soul alone decides what to experience and learn during each earthly sojourn. Each life experience is often shared with known souls from past lives, having similar Karmic configurations.
If we are selfish and greedy, we will experience losses whether in this life or in a future one. If we raped someone in a past life, we could experience this in some way in a subsequent lifetime. Inharmonious acts must be balanced now or in a future lifetime, in order to have soul growth.