At my office, if you don't answer your phone for an internal call (for example, due to being busy talking to another developer about a tough problem, or deep in

At my office, if you don't answer your phone for an internal call (for example, due to being busy talking to another developer about a tough problem, or deep in concentration on a problem) the person who called you will get up and come in to your office to see why you didn't answer. Really makes it impossible to have any solid development time.