I always marvel at the surprise or lack of awareness when people run into me or others when it is out of context or out of the normal routine. When people see me at the gym, walking around town, or in a public place, I often notice them, but they don’t notice me (and as I joke with whoever I am with at the time, it’s not like I am very inconspicuous).
When you run into employees or employers in a public place where they aren’t engaged in private dialogue, sitting at dinner, or giving off social cues that indicate that they don’t want to be bothered, it’s polite and normal to say hello and go about your business.
In the workplace, I think there often is the fear that we are invading people’s privacy by saying hello to them when they are out in public, but the opposite often occurs; if we can’t feel comfortable saying hello to someone in an unexpected moment, than how should we feel on a daily basis when we see those people at the office?