Everything in reality generally falls under something like a Bell Curve, with most events bulking towards the middle & averaging out, and extreme events, on either side, thus being more rare. Hence, bad days usually balance out with good days, and vice-versa, while most days & moments are usually pretty average. This reflects the simple random chaos of the universe. The only thing that can change the Bell Curve is intelligence, and we humans just happen to be nearly the only observed creatures around who have any (even if we don't always use it). There is no greater intelligence to the universe, just creatures evolved within it who can be to some degree intelligent & manipulate their environments.