I expect you didn't mean this to sound condescending, but I found it to be exactly that. Who are you to judge whether people are civil, kind, polite, nice, based on whether or not they smile at you? You don't know their life. Who are you to say that they find it "too much of an effort" to smile at you? Maybe they don't want to put any social pressure on a stranger to respond to their unsolicited gesture. Not smiling at strangers doesn't mean that you don't acknowledge them as human beings, it just means that you don't expect them to want to interact with you just because you're feeling friendly. That pushy, intrusive kind of "friendliness" just doesn't exist here in the UK and I for one am glad of it.
Well I did say it was my opinion that people outside of London in general are more polite and they don't find it such an effort to be so. For example, if another person and myself happen to catch each other's eye as we are walking towards each other on the sidewalk, path, trail, walkway, bridge, stairway, hallway, whatever and I nod or smile, or god forbid perhaps even be so pushy and intrusive as to maybe say a hello or good morning and they walk right by me as if I do not exist, as if they find it too much effort to nod, smile, twitch an eyebrow, to make some sort of an acknowledgement, then yes, I will think that the person at that moment, is not a particularly civil, kind, polite or nice person and that is my opinion.
Same as if I held a door open for the person behind me and they walked right through and never said a thank you, then I would also think that is not a particularly civil, kind, polite or nice person, again, that is my opinion.
I am not talking about walking along a place such as Oxford Street or Times Square and nodding and smiling at every person I meet, I was saying, how in my observation, when I walk around my husband's quiet neighborhood in London and I meet the odd person on the same side of the street that very rarely does that person meet my eye (I am not staring that same person down waiting for them to look at me either).
I have lived/worked in Manhattan, Queens and the Bronx and if I happened upon a person on the sidewalk in a residential neighborhood, more often then not, one of us would nod/smile or say hello to the other person and continue on our merry ways, so when I saw the way it was in my husband's neighborhood, I found it odd.
I will continue to nod/smile/or say hello to random people if we happen to catch eyes, I will also continue to hold the door for the person behind me, say please and thank you, say hello to the bus driver or taxi driver, waitress/waiter or the cashier at the store, not talk loudly on my cell phone, keep my elbows off the table, expect other people at my table to do the same and take their hats off, give my seat to the elderly/pregnant or disabled on the bus/train/tube, help someone if they are struggling with a stroller or their bags, actually write a thank you card, rsvp when and how I am asked to do so, be quiet in the movie theater, pick up after myself, not litter, not leave the clothes I try on in the changing room for someone else to deal with, have respect and patience for my elders, use my directional, not tail gate, not cut someone off and let another car merge while driving, let the person behind with one item go ahead of me if I have a full cart to check out at the grocery store, not take someone's parking space, say excuse me if I walk in front of someone and generally try and travel through the world in a civil, kind, polite and nice way.
So to think that I am condescending towards people who don't respond to a simple nicety are not civil, kind, polite or nice and that they are so self absorbed that they can't be bothered or it is too much effort to be civil, kind, polite and nice in return, well, you have your opinion and I have mine. As for me saying that I do sometimes actually nod/smile at a odd person that I pass on sidewalk if we happen to look towards each other & catch eyes and having to defend myself for saying this and finding it not to be polite if the same person doesn't respond in some way, well, I dunno, sadly maybe I am in the minority for thinking its an okay thing to be polite.