Responses in this thread have been pretty interesting. While the premise of the thread might be lulzy and uninspired, I actually find the simple act of just walking down a hall to be pretty entertaining and illuminating—largely because I've pretty much encountered every single type of behavior mentioned in here.
I can respect people not wanting to engage with anybody in such an environment. What kinda miffs me though is the ones you do lock eyes with and smile to, who clearly saw you smile and say hello...but seem to project an air of either being better than you, or too good to respond back. Or, they'll have a face about them like they just heard of a death in their family. Smile, damnit!