To elaborate on this, the Schrödinger equation, which describes the dynamics of a single particle, is a wave equation and hence a lot of classical intuition from e.g. electrodynamics can be applied. It is many-body systems, i.e. systems composed of many interacting particles, which is not only mathematically complex but can also defy classical expectations due to emerging phenomena, etc.
Slap a "quantum" on it = Instant flux capacitor (mander.xyz)