Quiescent galaxies (QGs) typically have little cold gas to form stars. Thediscovery of gas-rich QGs challenges our conventional understanding of theevolutionary paths of galaxies. We take advantage of a new catalog of nearby,massive galaxies with robust, uniformly derived physical properties to betterunderstand the origin of gas-rich QGs. We perform a comparative analysis of thecold interstellar medium and star formation properties of carefully matchedsamples of galaxies with varying degrees of star formation activity and gasrichness. QGs with different gas content have virtually identical morphologicaltypes, light concentration, mass-size relation, stellar age, dark matter halomass, and black hole activity. The only distinguishing characteristic is theenvironment. Gas-rich satellite QGs reside in a lower-density environment thantheir gas-poor counterparts, as a consequence of which they manage to retaintheir gas and experience a higher probability of cold gas accretion or gas-richmergers. The environmental densities of central QGs are similar regardless oftheir gas content. We suggest that the cold gas resides mainly in the outskirtsof the gas-rich QGs, where bars, if present, cannot transport it inwardefficiently to fuel central star formation. The prominent bulges in gas-richQGs stabilize the cold gas from fragmentation and leads to low star formationefficiency.