Caroline mentioned Bell's Inequality.
Bell's Inequality and EPR (Einstein, Podolsky, Rosen) both show not that quantum mechanics is wrong but that it is incomplete. There are some missing ingredients
Take angular momentum for instance. We know that the angular momentum of a spinning object depends not only on the frequency of the number of rotations that it makes but also on the mass of the object. But quantum mechanics forgets mass entirely and simply equates angular momentum with frequency alone.
Quantum theory has too many of these missing ingredients.
Yet it tells us that the spin of an electron is quite different from the spin of the earth.
I guess this would SEEM true when you are not using all of the ingredients.
Once you realize that the electron gets its intrinsic inertial mass from surrounding electrons, the same as our mass is derived from our surroundings (Mach's principle), and then you also give the electron gyro torque; guess what happens?
You can derive all of the electrical laws simply from this gyro torque.
I saw and published this in 1966.
So you are never going to completely understand the electron, or for that matter anything else, via a theory with missing ingredients.
Every theoretical physicist is going to tell you the spin of the electron is different from the spin of a top even though their own science negates the necessary ingredients to make the spin similar.
So I consider the electron - if it could be viewed in its own reference frame - as being a spherical particle with gyro torque.
Viewed from our realm, however, it can be viewed as a spherical standing wave or even as Gabriel's plum pudding.
It depends on the resonance - oscillator frequency - of the viewer.