In what is sure to be the first of many posts involving that most revolting of habits:

These wannabe pacmans can be found anywhere-- even within the confines of an allegedly "professional" environment where this behavior is shockingly permitted but mild sexual humor is not.  Their industrial-strength jaws can be seen clamping shut and then dropping back open in a rhythmic mechanical motion that must be of aerobic benefit.  The default curvature of their lips is that of a smirk-like rictus that suggests insincere merriment and unwarranted self-regard.  What's worse, the offending wad, jouncing among these hard-working bicuspids, seems constantly in danger of spilling out and making its home wherever it lands (urinal, subway platform, etc.-- related entries to come).