There is no separation between you and other people. The illusion of separation comes from our egos which makes us see the world as the central being. Other people are simply other manifestations of our true self (the universal absolute).
Other manifestations of yourself
The other creatures you meet your life are in fact other manifestations of yourself (the universal absolute as your true self). They are your alter egos. The type of people you will meet will be in accordance to your ego's karma. They represent an aspect of yourself just like the people you meet in your dreams.
The continuity of interactions
New people you meet can be the continuity of other people you knew before but can also be the reflection of how you behaved toward someone you knew before. For instance, your oppressor may be a projection of a former behavior of repression (the same is also true for positive kind of interactions). There is in fact no separation between people, and as you move from one place to another, your former relationships will be continued on other people. Be kind to others because they are your long lasting partners. The continuity of relationship is however very dynamic and some aspects of a former relationship with the person "A" can be represented person "B" while some other aspects will be in person "C".
Mirror continuity of interactions
Because others are manifestation of yourself, the way you treated person "A" can also be manifested on person "B" and you will have to opportunity to learn from the point of view of the other person "A". One must be attentive enough for this kind of experience to be useful for spiritual growth.