Karma is not about good versus bad, nor is it punishment. The idea behind karmic interactions is to experience both sides of an equation (such as teacher/student or attacker/victim) until we achieve neutrality and balance. Typically, older souls are seeking to redress any outstanding karmic imbalance and arrange their lives at the level of soul to achieve that result. This often leads one into the role of wounded healer.
While it can sometimes be challenging to determine whether or not karma is in action, one indicator is that the situation is charged with emotional reactivity. Once the lesson is complete, we become neutral about the other person or event and can interpret it with wisdom, compassion, or gratitude.
We often have empathy for others who are going through something that we, too, have experienced. While one may not consciously remember past lives, the energy and insight we have gained from them is part of our energetic field. This is why older souls have the ability to step into compassion and also why younger souls cannot. We only learn through experience.
Act with integrity, do your best and accept what is. This is the pathway to understanding and unconditional love.