The four fundamental forces of nature, the strong force (the glue of atoms), the weak force (radiation), electromagnetism (electricity, light and magnetism and the repulsion that stops atoms fusing) and finally gravity. Those four forces govern the universe as we know it. Some other stuff is involved like the Higgs field which is omnipresent and gives mass to everything and also dark matter and dark energy which make galaxies spin properly.
Of all the forces in the universe gravity can be considered the strangest, its not what you think it is, it's not two objects which are attracted to each other, like two magnets are. Objects are not attracted to the Earth. Imagine gravity as a depression and you are constantly falling into that depression, like a never ending slippery slide. The electromagnetic force stops you falling as the atoms in your foot repel against the atoms in ground. You actually never touch the ground. You are hovering by a picometer due to strong force. On top of gravity strangeness is its ability to warp time as you get close to large celestial objects. However gravity is a force that brough order to the initial chaos of the universe by lumping matter together and out of that initial chaos came galaxies, solar systems, planets and eventually light. We can thank gravity for that.
What I love about the universe is that it's just beyond humans to understand. Second there are particles out there that don't at all interact with matter. So we can't see them, touch or feel them, we can just barely study them. Like the Higgs field. The vacuum of space is not empty as people suggest it's full of Higgs Bosons (particles). You have trillions of neutrinos passing through your body every second, but nothing happens as it does not interact with matter. So what we see is not everything. We only see a tiny slither in the electromagnetic spectrum. We are only starting to understand the universe and our place in through our instruments which can see in the other parts of the electromagnetic spectrum.
There is also the strangeness that particles can pop in and out of existence, for a brief second they can be created out of nothing. How can something come out of nothing? Our brains evolved on the plains of Africa running away from predators. Lions don't pop out of nowhere. Our brains evolved to figure out where predators/danger come from so we can stay away from that area. So our minds have build in "cause and effect" as a standard program in the mind. Like your iPhone comes with a standard suit of programs. The is no program for understanding things popping out of nothing. It would be nothing short of magic, but thats what particles do all the time.
Particles however can pop out of nowhere but energy has to be conserved in our universe so the particle goes back into non existence and fast as it came into existence.
There is also the strangeness that we do not know where the electron is in the atom until we observe it. We have probabilities about where it might be but thats about it.
The most fascinating thing is that it all comes together to make us and our brain and the trillions of synapse connections. The universe becomes aware of itself and then it's trying to figure out what it is. It's like you woke out of coma and you don't know who are, and you are trying to piece you past life together. The universe is doing the same thing.
Maybe some other parts of the universe has figured it all out but we are still far from it.