Every system has a finite set of terms of references, or we could even call it an interface, that enables elements within the system to interact again with a finite set of objectives. The objectives could vary from cooperation, to the opposite where you do agree not to cooperate and fail in a graceful manner or even mutual neglect. The success of the system is entirely dependent on how well one can compress the maximum number of possible terms of reference into the minimum number of symbols, signs or anything else you can choose to call it.
Even if the world functions in a strictly non-binary way, I could wake up feeling 'slightly' more happy than what I woke up yesterday, the end result is always strictly binary, I could only have woken up happy or sad. Even vague is slotted into either. Ultimately, how successful you are in a system is entirely dependent on how well you can converse naturally using the terms of reference. Natural is important here because when things are pushed to the specific nothing is binary, every instance differs, so you should not have the time to think. You can only believe.
If you cannot believe, then we have a problem, rather big one at that. Because how do you know what you see is what another sees. What is orange other than a word that represents something of a certain colour, as agreed to by the majority. That way orange could even be yellow and still be the same if enough of us willed it. But that is another story. In the same way, like representations, relationships too require you to believe. We function based on these beliefs labelled into finite categories and if you do not believe, tough luck, you lose.
In a lot of ways, the things that we keep close are often the thing that pulls us farthest. We are scared. Systems do not react well to non-binary infusions and if you are not willing to take the risk of walking on the edge, it is very likely that you would end up freaking out over a system totally clueless as to how to react. The interface does not have a term of reference. Abort, Retry, Fail? The nature of the way the system is designed ensures that such instances are minimalised with a possible nearest match to a finite term available as close as possible. Failsafe? No. Graceful failure? Yes.
That is why we look for signs to tell us that we are not alone, that there is a greater purpose to what you cannot make sense of. Often, our failure to fit things into a known context leads us to look for greater or alternative meanings and agendas that makes it all sensible. You could thus be communicating with people on other planets or live in hope of having a greater truth or purpose to your life explained to you at some point in the future, just because your immediate context does not make sense. This was not the way it was not meant to be.
Thus interpreted, destiny or fate is not what is slated to happen, but what is core to you that you always sidestep. Or alternatively, it is what you believe in at the core than what is peripheral. It is the eventual finite term that you lock yourself into, be it in terms of career or your normal life. One is always either a "great doctor", "a good father", "a funny person" , the list can just go on. If you do not believe, you are either cast out under other broad terms like crazy or if you are smart, you fit into the fringe, just under the limit that tips the scales over the permissible margin of error.