What rare the exceptional cases in physics?

Answer 1

If what you mean is... are there any excepts to laws and rules in physics, then yes... and no.

Things become very blurry at the "boundaries" between classical and quantum physics, so particles can behave as waves when they can occupy lower energy states by doing so. Waves can behave like particles when they interact with matter at a similar size to their wavelength.

But generally, fundamental laws, like the conservation of energy are (without exception) obeyed by systems.

Answer 2

Some exceptional cases in physics include phenomena like quantum entanglement, where particles are correlated in ways not explained by classical physics, and black holes, where gravity becomes so strong that even light cannot escape. Another example is superconductivity, where certain materials lose all electrical resistance at very low temperatures.