The uncertain and unpredictable nature of life is something that we take for granted. From the day when we are born, uncertainty dominates our life. What do we look like, do we cry a lot, do we have that mole at the back of the leg or do we like to sleep on our tummies. To us humans, everything is an unknown till it happens. Either consciously or unconsciously this is one feature that Allah has put into all of us humans.
One might argue that this is not true, because you remember an instance of an aunt or a friend saying "who knows what will happen". Surely, this implies that they did not take anything for granted. However few are privileged to be conscious and aware of this thought be it briefly. Having said that, even these same people forget about their own claims of uncertainty in due time. Because, the truth of the matter is that in order to be "aware" one has to side-step life and that is something that can only happen briefly,at least for most of us who want to be "functional" in the human society. When we hear somebody disclosing this principle of uncertainty they have chosen to step away from this constantly flowing stream of events and take the time out to think about this. And once disclosed, discussed and analysed they go back to the stream.
Perhaps this is the mindset of sages or wise-men. They have acquired the ability of meta thinking, over time. They are on the pavement counting the cars that pass by, instead of choosing to be part of the traffic flow and occupying their minds constantly about dodging others. They are not only interested in thinking about things but instead analyse those thoughts or the outcomes of those thoughts. While the rest of the world is busy pointing fingers at them and calling them names, they are weighing the effects of these unpredictable scenarios.
An average person when faced with an unexpected outcome of a life event would generally be heard saying "life threw me a curve ball" or something along those lines. But really, it is just life as it has always been and always will be. Nothing exceptional has happened. Even if a distasteful event occurs in your life, there was an equal probability of it being an exceptionally pleasant and rewarding experience, from our point of view. The key here is "our point of view" because we as human beings do not have the ability of knowing what Allah has in store for us. So for ourselves, at least, everything is unpredictable and uncertain.
Like a dry leaf we ride the gusts of wind not knowing the ultimate destination.