It's a very anthropomorphic question. Every action we take follows previous events. There is a why to our behaviour even if it's convoluted or unclear to us. Naturally, we expect the same in the world around us. Every object, action, event, must have some explanation.
Yet I wonder if this obsession with "why" limits our outlook of the world. We seek clear answers above all else. And shun ambiguity as insufficient. So instead we focus on finding the explanations for everything around us. Science is built on asking questions and challenging hypotheses. But does this approach work as well in daily life?
We wonder why someone acts in a particular way. Or what the motive behind their words is. In many cases, it's impossible to truly know. You either ask and trust their explanation or find your own and believe it.
Would it be better then to accept these actions for what they are? Ignore the why and focus on the results and your reaction. Our actions are not always logical, and the why isn't always obvious. Yet an eventual explanation can change your view of someone's actions. Maybe the best response then is to assume the best intentions, react accordingly, and await the explanation instead of trying to find it ourselves.