I believe for most of us there is more than one real purpose for being here on earth. We have a purpose that is related to our own growth and we have a purpose that includes our interaction with others including resolving karma. Many times both purposes fit together in some way. Another thing that confuses us on the subject of life purpose is that we so often think it is what we do rather than what we are being. You can explore your life purpose no matter what job you have.
If you think of life purpose as something that involves states of being, it may be more clear. For example, you might have a life purpose of exploring forgiveness, love, acceptance, growth, discrimination, flow, dominance, submission, or re-evaluation. Each one of these explorations in life would look very different.
For example, if you chose forgiveness as a life purpose you would most likely have interaction with people who do things you think is unforgivable. As you explore your purpose and challenge of forgiveness, you begin to understand how embracing forgiveness frees you from those people who have hurt you and helps you create clear boundaries that prevent further “unforgivable” actions from those people. In this way you have not only mastered the lesson of forgiveness, you have also learned about re-evaluation, discrimination, dominance, submission, self-esteem, self-worth, self-acceptance, and personal growth even though most of those life challenges were not your life purpose priority.
In the process of meeting the challenge of your life purpose, you have offered the people you interact with an opportunity to explore the purpose of their lives. Perhaps a person who behaved hatefully toward you has a purpose of exploring divine love. Your ability to choose forgiveness and love for yourself offers a shining example of divine love for them.