The stairs maybe singularly interesting as a novelty or curiosity, but to gain better perspective, you'll want the stairs, hallways, entry/exit-ways, etc.
If you can gather data of human traffic flow around the workplace in all sort of spots, you can then analyze that data to gain perspective on that flow. And it's not so much of the obvious patterns, but maybe those that didn't seem obvious (until hindsight after the fact). Proximity and placement of different facilities (printing/copying facilities, toilet facilities, lounge/kitchen facilities) within the office space can lend to different interactions or even wasted time.
And, of course, one can casually observe and make qualitative observations. But those qualitative observations may not necessarily be impartial nor rigorous in their recording. To avoid subjectivity and anecdotal evidence, quantitative evidence through raw data recording aids in eliminating potential subjectivity.
Based on this, you may choose to layout the office space differently. Or when choosing a new office, you may better know certain attributes you're looking for in a space.
For example, Pixar's centrally located toilet facilities intentionally shape traffic flow with the intent of increasing interactions among employees for facilitating potential conversation and discussion.
As shiftpgdn mentioned, another example seen often is stairs vs. escalator/elevator usage for encouraging subtle, healthier choices. The counter, when displayed publicly for those respective areas, can serve as a mechanism for real-time, interactive feedback to the observer. Confronted with this reminder, it may coax them a little, giving them the little mental kick to use the stairs instead.
Maybe you determine that if you put an appropriately shaped obstruction — e.g., a wall with a sign of company logo — carefully placed immediately in front of the entryway, it may result in better flow through the that area. Notably, it might encourage people to not stop in the doorway, blocking; but rather proceeding further into the lobby area to converse.
Although more of a larger crowd thing in this example, studies have been done in this area and have demonstrated such results: http://www.americanscientist.org/science/pub/strategically-p...
Related reading:
"Handbook of Positive Behavior Support" by Sailor, et al.; "Behavior Supports in Nonclassroom Settings" chapter, "Features of the Physical Environment" section (page 499).
"Office Planning and Design Desk Reference" by Rappoport, et al.