We all know that humor plays many roles in our lives. Not only is it useful to entertain and to amuse, but it can also serve to break the ice and put people at ease. It can ameliorate awkward situations and assuage tense ones. For this reason, it's viable as a consideration in communicating with diplomacy and tact. There is not a large body of research on humor, but much of it centers on humor in organizations, like the workplace.
Robert Sutton (2007) succinctly documents the destructive power of workplace abuse, tyranny, harassment, aggression, and bullying in his book The No Asshole Rule. His solution to this trying situation is to avoid selecting the toxic people that tend to engage in this sort of behavior, and if you encounter them in your organization, run them out. Sutton's "rule" is built on the premise that interpersonal behaviors, even if relatively minor in isolation, can produce a significantly cumulative effect that damages the organization's climate and ultimately, performance.