The issue of rudeness in the workplace is starting to get more attention, as this article indicates.
In addition to otherwise nice people who are pressed for time and who often don't recognize how small oversights may appear rude, there is the corrosive nature of a society where the put-down is raised above simple kindness and where the cult of Me First and Foremost has a large membership.
I sometimes see that in classes. A person in a supervision workshop gets upset because part of the class deals with what he sees as the unnecessary topic of time management, all the while missing the fact that many other class members want help in that specific topic. There is an inability to get beyond self that can be jarring. Our society's marvelous ability to customize products and services to please every taste may foster the attitude that every experience should be customized and there should be no trade-offs. You see many teams that are collections of independent operators instead of a blend of collaborative participants. When that environment exists, rudeness can flourish.
[Hat tip to Business & Legal Reports.]