What is it that caused your great-grandmother on her meeting with your great-grandfather to recognize him as her future mate and the future father of her children? You can call it a mystery, but it is a mystery that does not imply doubt. We can presume she felt something definite. She felt affinity.
How about the complex of affinities that bring you to a bank just as a robber comes in? Are you responsible for this situation? Lots of incidents led up to it, and once their results are in train, you might have no control. There is such a thing as world karma. I as the world am responsible, but there might be no way for me as an individual to help once the crisis has become acute.
It is time to turn to the traditional teachings, if you are so inclined, or simply to search on your own. Take heart, and from your own heart and mine we can weather this war that ranges all round us, and together we can embody and present the Way.
Chance and destiny are not adequate concepts for explaining karma. It's really a dance, isn't it!--a dance of sisters and brothers who come together by mysterious likeness and attraction. Their dances in turn come together with all the dances across the world. For some this can be joyless, even the dance of exploitation and murder, but for the Bodhisattva it is the great cotillion of intimacy.
Affinity, affinity. All beings are made up by affinity. The whole universe, through every dimension, forms a vast net of affinity that is all of a piece--a multi-dimensional web. With any movement within the web, everything moves. Each gesture, each blink brings a new kind of equilibrium and new kinds of interplay throughout the net. This is a never-ending process from the unknown past to the unknown future, and through all other dimensions including the eternal present. Touches that bring joy and harmony bring new interplay and new equilibrium. Touches that cause suffering and death bring new interplay and new equilibrium as well.