What do you think is the main value of psychology? explain your answer?

This should really be from your point of view but as a psych minor I can say that the main values would be the ability to understand human development and overall health
Before psychology was actually considered people who had mental illness were not diagnosed, they were just locked away in a typical half way house for people who did not fit the 'norm; of society
Lobotomy was the general cure for someone who today we would call 'schizophrenic', these people were not treated as people and were not allowed everyday freedom in society as they are now. 

Thanks to psychology we know that newborns need to be held and need skin- to- skin contact in order to develop healthy emotional bonds with their caregivers. we know that the average human needs about 7 hours of sleep in order to hit deep sleep and re-energize their muscles. psychology makes it easier to understand different people and to understand and express our emotions. i could go on forever but limited space here, feel free to msg me on this site if you need more info.