Rotation of rigid bodies is a phenomenon we repeatedly encounter in everyday life, yet its physical description remains conceptually and mathematically difficult for students. Principal axes and moments of inertia can be especially challenging concepts for the general case of an asymmetrical and inhomogeneous body, because it is difficult to provide physical reasons why some axes may be preferred over other. As a consequence, we often resort to symmetrical solids and ask students to rely on their intuition or experience while considering the mass distribution relative to the rotational axis. We may also conduct an experiment in the classroom using, for instance, a rectangular parallelepiped to show that the amount of work to reach a given angular velocity depends on the chosen axis of rotation.