  A broad survey of viscoelastic data demonstrates that van der Waals,
hydrogen-bonded, and ionic liquids, as well as polymeric, inorganic, and
metallic melts share a structural relaxation pattern virtually insensitive to
their morphological details. This mechanical simplicity is connected with that
characterizing the fast reorientation dynamics prevailing in liquids devoid of
a distinguishable secondary loss peak. By these means one is able to uncover a
generic spectral pattern which rationalizes the recently reported
"universality" of relaxation strength vs. stretching of the dielectric response
of viscous liquids, significantly broadening the framework in which their
relaxation behavior is assessed.
