I understand that one can be oblivious to someone they should acknowledge by means of greeting or at least making eye contact and shaping one’s mouth into a slightly upturned vestige of a smile.
There are many a time when I may not see someone until the very moment that our profiles are almost exactly parallel to each other - that is to say, the moment before we pass each other.
Sure such last-minute eye contact will result in an awkward turning of the head over the shoulder and a scream-like “hi, how are you” from both persons. Both will continue to walk, most likely in opposite directions, and both parties will not expect an audible answer akin to, “I’m fine”, from the other…
…but, it’s a mutual awkward obligation that also satisfies the primordial human need for non-combative human contact.
I also understand those times when you consciously try to avoid someone.
More times than not, I have avoided people; I was aware of their presence nearing my own self.
Sorry, but I was not in the mood to communicate.
I’m not in any mood to communicate a blatant lie about not feeling as I truly feel - whether that be upset, helpless, homesick, unsure, contemplative, or more positively- giddy and/or dreamy.
I do not wish to communicate with you in a way that would cause you to believe that I am reacting to your being, when in fact, I am predisposed to the circumstances that were-
prior to me coming into contact with you…
… but I don’t blatantly, in front of your face, under your gaze, or in your periphery, ignore you.
I dislike socializing and small talk, but I also do not wish to make life more complicated by creating an awkwardness.
In this situation, you would probably indulge in the idea of taking the initiative to adhere to what is accepted as correct social propriety, and so you acknowledge him/her - that irrelevant person who you really could care less about-
You give him a simple nodding of the head, a semi- smile, or a blink that successfully satisfies their need to be noticed -
In their defense, to be noticed is a universal human need that has to be satisfied. (The degree to which it must be satisfied is what differs from person - to - person.)
So you acknowledge that person who is someone you neither love nor is in anyway related to you = he/she is irrelevant.
All the while this irrelevant person, with the dilated eyes, is exerting energy into firing brain-derived synaptic signals for the sole purpose of deciding how to deal with you -
You - that unwelcome an/or unexpected passerby-er.