The Middle World
One should not confuse 'middle world' with 'middle earth' the famous stage for the events in Tolkien's LOTR and 'The Hobbit'. The middle world is more of a snippet of the spectrum of environments which exist in the universe, most notably on our planet. Humans, and our evolutionary ancestors, have evolved over millions of years in certain environments all with differing selection pressures. These environments varied in temperature, population dynamics of other organisms, predator - prey ratios and amount of food. However all the environments that our mammalian ancestors shared all depict physics that are more apparent on a certain scale level. For example the evolutionary ancestors of certain bacteria lived in a 'small world' where the sizes of the organisms were closer to the size of the molecules that make them, hence the random kinetic motion of molecules (known as Brownian motion) is more apparent than on our scale level. Brownian motion is not so obvious to the human naked eye. The middle world is the environment we are accustomed to and includes the normal speeds of objects which we are used to observing, the air resistance which impacts every object and something which our brain has not evolved to conceive without.
As we did with the scale level of bacteria we can postulate other worlds i.e. spectrum of environments which would make some physical laws more obvious than would be in our middle world. Let's postulate, for the sake of a thought experiment, that there could exist organisms which were the size of planets and they evolved to survive in a planetary environment. What physical laws would seem more obvious? Well we think of which forces are stronger with increases in mass and size.... Gravity! Yes the strength of gravity between objects is directly proportional to the masses of the objects. So this organism would evolve in a world where its gravitational force on other objects is significant and could easily witness the bending of light due to gravitational forces. To this organism most of the consequences of Einstein's general relativity would be 'normal', however if this organism were to develop science and look upon our middle world where objects travel faster and other forces stronger than gravity exist it would look strange.
The world was not made for us
Our own evolved perceptions of the world are just that.... evolved perceptions. We do not see the world as if it was intelligently designed for us or made just for us by some supernatural being. No, we ourselves are products of the universe and the laws of physics and as such will find layers of reality that will behave completely differently to our 'middle world'. The fact that our perceptions of the world are so so adapted to fit a certain scale level of the world it almost seems natural to think the world was made for us. But 'seeming so' and 'feeling so' are not what gets to the truth about the universe... we need 'knowing so'. So as we use empirical and sensible techniques and apparatus to study the universe, apparatus and techniques that go beyond our adapted senses, we will contact a layer of reality which we have adapted no set instincts or genetic programs to comprehend. However our brain is so adept... so versatile and ingenious that we can understand it. In order for us to keep developing our comprehension of the universe we must not care about strangeness or oddities but simply stick to mathematical and scientific rigor.
There are a lot of strange phenomena in the universe which by our previous discussion fall outside the middle world of our perception. Most of these strange things occur at the extremely small scales of physics or the very large or even the very very fast and the very very slow. For example the process of natural selection itself i.e. the struggle for survival of genetic material against selection pressures is an extremely slow process. If we take the complete evolution of the horse (from some arbitrary starting point with physiological sense) the process took approx 50 million years which is about a million times as long as the lowest life expectancy of a human being. So of course the continual change of organisms, which we have not and our ancestors have not witnessed in one lifetime would be very strange to us.
Quantum Mechanics is one of the fields of science which many have been quoted in saying it is the strangest. On the atomic and subatomic scales of the universe we would expect a completely different world. Clouds of electrons whizzing around the atomic nucleus with no decided place unless perturbed by some external probe (other particle). Atoms attracting one another but strongly repelling upon close impact. The fact that quantum particles which are considered to be part of the same spin system, continue to conserve spin arrangement even if the particles are moved to either side of the globe (Quantum entanglement).
In special relativity we witness the slowing down of time relative to faster moving reference frames... and the contraction of lengths of objects as they reach the speed of light.
As we continue to delve deeper into the construction of the universe or expand our time and size scales to galaxies and even multiple universes we will witness strangeness... until our scientists become 'adapted' (not genetically of course) to that world of perception. We should all be searching for strangeness as that's where new layers of reality will be hiding.