One of the best parts about running is that we runners always have a sense of community, even when we're running alone. It's not unusual for us to acknowledge other runners as we pass them on the trail or during a race. I always try to at least make eye contact with my fellow runners. Often a simple greeting is exchanged. The other day, while running at the High Bridge Trail, there were a lot of "Good mornings," though a couple of times I heard a "Good moanin" instead. One runner even had a New York accent. Didn't matter, we were all out there crushing it. Of course, there are variants on "Good Morning." Toward the end of a run, a nod and a smile might have to suffice. When you've begun to get really tired, a wave of the hand is about all you can muster (wave of the hand = wassup, this is really hard). Experts call this "phatic communication." Often called "small talk," the purpose is to establish a mood of sociability rather than to communicate information.
At your office today, why not try a "nod"? It might come in the disguise of spending a couple of extra minutes sharing pleasantries in the office before going to your desk. "How was your Fourth of July weekend?" is another form of a nod. We may work alone, but the community we're connected to is a large part of what keeps us on track.