First what we can notice in physical existence are different, separate, material living and non living beings. Although all those individuals appear independent, it is not so. All those individuals make one system or physical existence.
They are all conected with direct or indirect interaction what is necesary not only for every individual in whole but also for whole. One without other can't exist. We can start from our planet.
Planet Earth has characteristic chain of dependence of all living and non living beings. They interaction is necessary not only for each other but for existence of planet. Further, planet Earth has it is own place and function in interaction with sun and other planets in our galaxy, as our galaxy has own purpose with other galaxies and so on.
All what exist in universe is directly or indirectly conected.
There is no an accident. Every relation with other people, animals or surrounding have purpose even when appear to be very destructive. Every such disharmony is oportunity to better adoption not only for individuals but for whole. Everything is in progress, therefore everything have specific interaction in that progress.
Human consciousness must evolve to understand that union, dependence and connection with everything what exist and act in interest of whole not only on illusionary separate interest. That is the only way to make harmony not only in whole but in himself as part of whole.