Layer styles are useful because of their parametric and their non-destructive natures. Smart Filters are useful, but require the creation of a smart object beforehand. I'd like to suggest new layer styles, of commonly used effects, that would help to automate time-consuming tasks. Cast Shadow would simulate the shadow casted by a light placed in front or behind the object/layer. It would use most of the controls found on the proposed Mirror layer style (point of origin, distance, angle, blurring, fade, shrinking, enlarging...)I hope that other users will chime in with proposed refinements, or create other threads with additional (useful and feasible) layer styles they'd like to see.