The dynamical spin structure factor measured by neutron scattering is a powerful tool for understanding magnetic insulators, yet interpreting this linear response function remains a significant challenge. What quasiparticles govern it? What does it reveal about magnetic or topological order and entanglement? How do spatial (quenched disorder), thermal, and quantum fluctuations interplay—and can they be distinguished? These questions lie at the heart of current research, where advances in materials, computation, and experiments suggest that quantum effects appear more pervasive than previously thought. This talk will explore neutron scattering studies of triangular-lattice magnetic systems, ranging from quantum spin-liquid candidates to multipolar magnets. Our findings show that semiclassical simulations often offer a remarkably accurate framework for describing spin dynamics. This approach not only provides a microscopic understanding but also enables us to precisely identify the conditions under which genuinely quantum phenomena—such as magnon decay, magnon fractionalization, or the emergence of exotic quasiparticles or gauge fields—manifest, if at all.