Why the quantum world is so strange

Reality can be strange especially at the scales but causes it to be that way physicists used to pin it on quantum entanglement but there may be deeper source quantum discord when two photons are entangled they share a sort of information link each has information about the other and when that information change like when one of the photons is measured that new information is reflected in the other photon almost instaneously any noise coming in form the outside removes information from the connection untill there's not enough left to maintain the link but it turns out that entanglement is only one kind of connection that particles in the quantum world can have quantum discord another if entanglement is a perfect link discord is a less than perfect link it does not carry as much information but still lets quantum particles interact in ways that classical particle can not the more discord a system has the stronger its quantum behaviour while a system with no discord behaves classically with no quantum effects so the amount of discord is what determines the quantumness of a system  and when two particles are linked by discord it becomes possible to change one by manipulating the other this means discord might be useful for things like quantum computers which now relied on delicate entanglement to work quantum discord is more fundamental than entanglement and scientists are only beginning to understand exactly how it gives rise to all the strangeness the quantum world but one thing seems clear discord is more just a way to link quantum particle it's one of the rule that govern the most basic levels of reality