There is a very old Sufi story about a man whose son captured a strong, beautiful, wild horse, and all the neighbors told the man how fortunate he was. The man patiently replied, "We will see." One day the horse threw the son who broke his leg, and all the neighbors told the man how cursed he was that the son had ever found the horse. Again the man answered, "We will see." Soon after the son broke his leg, soldiers came to the village and took away all the able-bodied young men, but the son was spared. When the man's friends told him how lucky the broken leg was, the man would only say, "We will see."

... The cultivation of gratitude frees you from being lost or identified with either the negative or positive aspects of life, letting you simply meet life in each moment as it arises. In everything give thanks. From your limited perspective it is not possible to know the outcome of any event. What can seem unfortunate at first may turn out to be an unforeseen blessing.

"The Guest House" by Rumi
This being human is a guest house Every morning a new arrival A joy, a depression, a meanness, Some momentary awareness comes as an unexpected visitor, Welcome and entertain them all! Even if they're a crowd of sorrows, Who violently sweep your house empty of its furniture. Still, treat each guest honorably. He may be clearing you out for some new delight.
...The Essential Rumi