Below is one of my more fun answers on Quora. Most of the things I mentioned are fully explained by science, but in the spirit of the question, it’s more entertaining to call them glitches.
If, as Elon Musk suggested, we’re all part of an alien video game, can you identify any potential “glitches” they’ve made?
Below are just a few glitches I can think of:
- How bicycles stay upright is a mystery 
- Boiling water freezes faster than cold water in some cases 
- Negative temperature is somehow infinitely hot 
- There’s a lot more matter than antimatter in the universe 
- Dark matter  and dark energy 
- The universe is expanding at an accelerating rate, and recently discovered to be even faster than previously expected 
- Almost anything to do with magnetic materials (ferromagnetism, superconductors, etc.) 
- Quantum entanglement (affect one entangled subatomic particle, and observe instantaneous effects on its entangled twin many miles away) 
- Quantum tunneling (subatomic particle has nonzero chance of suddenly being on other side of “impenetrable” barrier) 
- Saturn’s hexagonal polar storm 
- Space, time, matter, and energy may all be quantized, like pixels