  Geometric frustration is known to completely damage kinetic processes of some
of the orbitals (and their associated quantum coherence) as to produce flat
bands in the non-interacting systems. The impact of introducing additional
interaction to the system in such frustrated systems is, however, a highly
controversial issue. On the one hand, numerical studies on geometrically
frustrated systems of hard-core boson (equivalent to a spin-1/2 systems)
typically lead to glass or solid phases containing only local many-body
coherence, indicating the persistence of the damage in quantum coherence. On
the other, there continues to be noticeable claims of development of
superfluidity that implies kinetic flow of particles. To resolve this apparent
contradiction of great significance, we present a rigorous proof showing that
density-density interaction is incapable of defeating the geometric frustration
to allow propagation of those immobile particles, let alone sustaining a
superfluidity. Instead, the frustrated systems develop many $\textit{compact}$
many-body localized states as "many-body scars" that do not thermalize, making
them good candidates for storing $\textit{robust}$ and $\textit{manipulable}$
quantum information.
