I would say that mystery is important in everyone's life for a few reasons. First, it is the inevitable human condition, and second, it provides us with challenges.
We all have mystery in our lives, which is the future. We do not know what will happen to us. Certainly, we know the sun will rise in the east and set in the west. But the future is always a mystery in some way. What you will be, whom you will love, and where you will live are all mysteries at some point in your life. If everything were predictable, if the future were known, I don't know how many of us would be all that engaged in our lives. I think it is the mystery of the future that makes us want to get out of bed every day to see what will happen next. I know that is true for me.
If there are other kinds of mysteries in our lives, we usually want to solve them. We are meant to be intellectually curious beings. This can be a grand mystery that leads to an important discovery, such as the mystery of the stars. Or it can be a minor mystery, such as why that car has circled the block five times. In either case, we are intrigued and begin to investigate. The world is filled with mysteries, great and small, and we need them for our minds and our satisfaction in solving them.