The surprising thing isn’t that physics remain the same from one day to another, it’s that that fact is the reason for conservation of energy. There are lots of different symmetries for the laws of physics: the laws don’t change from one day to another, they don’t change from one part of the universe to the next, and they don’t change based on angles (e.g. if you snapped your fingers and rotated the entire universe by 10 degrees around some arbitrary point, the universe would continue exactly the same as before, just 10 degrees rotated). From Noether’s theorem, you can take any symmetry on the laws of physics, and use that to derive a conservation law. In those examples, that gives you conservation of energy, conservation of momentum, and conservation of angular momentum, respectively.
It is surprising only when you are not aware of the right definition of energy.
The energy is a ratio between "action" and time, where "action" is a primitive quantity that does not depend on the system of coordinates.
While energy can be computed with various other formulae, like the product of force by length, all the other formulae obscure the meaning of energy, because they contain non-primitive quantities that depend themselves on time and length.
So energy depends directly on time, thus the properties of time transfer to properties of energy.
Similarly, the momentum is a ratio between "action" and length, so the symmetry properties of space transfer to properties of momentum, resulting in its conservation.
The same for the angular momentum, which is a ratio between "action" and phase (plane angle of rotation).
