"Our wills and fates do so contrary run/That our devices still are overthrown; / Our thoughts are ours, their ends none of our own," says the Player King, meaning perhaps that for all we may do and think, the future is never entirely in our control.
Call it "fate" or "karma" or "God's will" or "blind chance" or "serendipity" or . . .. The name is not as important as the essential concept: Events often turn out differently than we had expected. Other factors, beyond our control, often shape our lives in unexpected ways.
That's not to say we are powerless to shape our lives. We can think and act with integrity, generosity, mindfulness, courage, persistence. We can do all this and more, but in the end who knows which of us will be struck by lightning or cancer? We are parts of a much larger whole that has its own inscrutable origins and ends.
We may not like this or think it fair, but if we can accept it, we can focus better on acting and thinking in the here and now without illusions or bitterness or regret.
Recall a time in your own life when you experienced an unexpected turn of events--for better or worse. Or if you prefer, tell about such a situation that has been in the news. Describe the situation briefly and tell what, if anything you learned from the situation.