We study the flow and clogging of soft particles: micron-sized oil droplets, centimeter-sized hydrogel particles, and simulated soft particles.  We find that softness is a key factor controlling clogging:  with stiffer particles or a weaker driving force, clogging is easier.  Softer particles form less stable arches and thus reduce the probability of clogging.  Our results suggest that prior studies using hard particles were in a limit where the role of softness is negligible, which causes clogging to occur with significantly larger openings.  In addition to softness, we also have some understanding of the roles of friction, vibrations, hydrostatic pressure, viscosity, and geometry… there’s a lot of physics behind clogging!