There are cycles everywhere you look. From sunrise to sunset, as you wake and sleep, cycles inexorably continue. From the clock in your computer, to the motor in your car (or the gears in your bicycle!), cycles are an important part of life.
We, humans, also have our own cycles. Our energy levels ebb and flow, our tastes change, only rarely do we find a food that we'd happily eat for every meal of the rest of our lives. And we have a three stage cycle of play, rest and work.
Zooming out a little, humanity has its own cycles too. "What we learn from history, is that we learn nothing from history." - George Bernard Shaw.We make the same mistakes our ancestors made, and if I were a betting man who would live to see the day, I suspect our descendants millennia from now will making the same mistakes we make today.