Life is very psychological - behind all the physical things we do, there's always psychological reasons, and usually a psychological impact, our physical bodies are merely machines that our psychological mind can use to interact with a physical world, as well as housing the mind.
I have had my share of issues, I think nearly everyone does to some degree or another, but we work them out over time, they dissapear, and we get stronger and eventually less confused, and we use our own experiences to help each other out and get into a more sane state of mind altogether. Any attrocities that happen are a sign of the insanity of mankind (at least those in power), as is needing something bad (i.e. needing oppression, needing challenge, etc). Furthermore, emotions aren't logical, and we get a better grasp on rationality as we harden. Emotions also warp out perspective, and can create needs.
The compulsion for me to say this is probably a sign of my own insanity. It is the existence of insanity I don't understand - how or why it happened.
But anyway, for whatever reason, people start life on this planet with room for growth, they hopefully get better and might be let out at the end - or put through more mental training until they are ready. I know some pretty sane and good people though, they might have come purely (or more) for the intention to help sort things out - if they gave up their place in heaven to come here, just to help people, that is a very noble and respectworthy sacrifice, but even so, maybe there is a chance to get even stronger while here- might as well!
I think we all shift towards a role more like that as we become less the patient and more the doctor
The odd thing is though, the insane mind believes it's sane, hence you get people more sane than normal people stuck in mental institutions on this planet because they aren't understood, and the parents may be afraid