Classically a particle has an intrinsic spin about some axis with an absolute direction. The results of measurements depend on the difference between this absolute spin axis and the absolute measurement axis. In contrast, quantum theory says there are no absolute spin angles, only relative spin angles. In other words, the only angles that matter are the differences between two measurements, whose absolute values have no physical significance. Furthermore, the relations between measurements vary in a non-linear way, so it's not possible to refer them to any absolute direction.
All directions are relative.
First, let's briefly review the QM case. Suppose we perform spin measurements on a series of particle pairs. Assuming each particle has a spin axis with an absolute direction, it follows that the correlation between two measurements can only be a linear function of the relative angle between the measurements. However, the measured results do not satisfy this additive property, i.e., they violate Bell's inequality. The object B is stationary, while objects A and C move away from B in opposite directions at high speed.