One of the worst things ever is when you're at work walking down a long hallway alone and then someone else starts walking down the hallway towards you, and the two of you either don't know each other or aren't really friendly.
What do you do?!
Stare at your feet/walls/hands/ceiling until you're close enough to make eye contact and say "hi" just before you pass them? Lock eyes and stare each other down until you're close enough to say "hi" just before you pass? Just pretend no one else is there and stay in your own world eyes straight ahead and ignore the other person?
I just don't know what to do in these situations. So I usually make sure I have my phone with me and am totally engrossed in what I'm reading on it.