Chaos is. IT IS. Oh yes it is. It is that which stops us from predicting our future perfectly. On a microscopic scale it comes from the inherent unpredictability of subatomic particles and radiation - there is no physical way to tell if a radioactive particle is going to emit radiation at a certain point in time or not. Its chances are always exactly 50-50.
On a macroscopic scale, that on which we live, chaos is more interesting, or at least applicable. It comes from the interconnectedness of everything - the fact that the movement of an atom on one side of the world will to some degree affect what happens everywhere else - like a drop falling into water, the ripples spread out to affect the whole body of water, although not always perceptibly.
You may be able to follow one ripple, sure, but consider that every single event (events are to be considered any change in an object, down to a subatomic particle moving, turning, speeding up, slowing down, etc) that happens propagates, and then combine this with the fact that we cannot predict the movement of subatomic particles, and you may be able to appreciate how chaos comes to mean a total lack of order or predictability. Events can be generally considered to propagate on their own scale and those above them - a blood cell doing the wrong thing could affect other blood cells and the body as a whole and then the body's world due to dependencies, but it does not affect the constituents of the blood cell or the atoms which they comprise of.
Chaos can and should be used to keep us on our toes. It has inspired "laws" such as the Law of Unfulfilled Expectations, which comments on unpredictability in the context of our hopes, and is linked with Triangulon's secret: Everything self-perpetuates.
It is also, to a perhaps less obvious (but indeed the beauty and insight of chaos comes out of its connection to non-obvious connections) degree with all of the known secrets:
- The World is Expecting Too Much links by way of the Law of Unfulfilled Expectations which is linked by way of unpredictability.\
- Laughing is always an option says that when things go absolutely nutsly out of hand, as they are prone to without any warning, laughter may be the best option and defense.\
- It's happening in the place links in that something is always happening, even if it's effects are not yet obvious (the something could be down to the level of simple random thermal movement of atoms and electroncs, but that's still a "something"), and the place is everywhere - something is always happening everywhere.\
- It's only my room if you're in it can be linked by way of the fact that this secret comments on perspective and its effect on the reality we perceive, and that chaos's effects are very much a matter of perspective - take the discussion of scale comparisons above as an example.\
- Impossible things keep happening this is in a way linked through the above secret in that whether something is impossibile is also a point of perspective. However it is also linked through quantum mechanics and barrier tunnelling, which states that even though it is classically impossible for a particle to hop over a barrier which it doesn't have enough energy to (think of a wall too high to jump over), there is still a possibility that it will exist past or even within the barrier (and this fact is indeed exploited, it's not just a mathematical peculiarity!) This can be scaled up, and indeed the probability scaled down proportionally, to say that impossible events are in fact just very unlikely - and chaos brings about unlikely events by its definition!\
- There's not enough fun to be had comments on the transience of everything - fun never lasts and indeed seems to go faster than non-fun so it would seem that there is less of it. Transience is the chaotic non-steady state, where nothing lasts and is unpredictable. Fun can suddenly become tears as someone loses an eye by accident, perhaps while enjoying a merry knife fight.\