Values define what is important to us throughout many different situations. They develop based on our subjective world view. As every individual has a different world view, every individual has an own mix of values with its own hierarchy. E.g.: For some of us, personal freedom is important. For others security, social justice or preserving nature is important.
We tend to experience positive emotions when we act in congruence with our values or when our environment also advocates them. However, we tend to experience negative emotions, when the opposite is true. Personal values develop throughout our lives rather subconsciously. However, the more conscious we get about them, the rather we are able to live in congruence with them. Scientific studies emphasize that living in congruence with the personal values significantly increases the chances to be personally successful and satisfied.