Cubicles have no doors

While I, unlike the heroes of this comic strip, am quite productive at my workplace, I am highly attuned to passersby. My back is to the entry-break in the carpeted wall, so my reactions are as follows:

1. When I do not have headphones on, I turn to look every time someone passes by;
2. When I have headphones on, I am startled by a tap on my shoulder by whoever needs my attention.

The first is less disruptive, but more frequent, so there is clearly an optimization problem buried here. In either case, it is clear why the principles of feng shui dictate that one should always have a clear view of the entrance to their space.