I've trained myself to do this stuff relatively well, but what the "convrsation has to be done my way or the highway, and anyone different is just fucking rude" posters don't understand is 1) it's fucking exhausting, and 2) if I'm doing a sparkling interested in you thing, you aren't talking to me at all. You are talking to my small talk algo.
The algo is handling the "here's an interesting but neutral question, now they've said X so ask about Y" part while I'm somewhere behind and all my attention is on arranging my face in the right expression, doing the right amount of eye contact, remembering facts you told me last time so I don't ask the same questions this time.
It's fun and I enjoy making the connection, but it's fun like, say, a game of high end football is fun, where what you are enjoying is your ability to predict next moves, react fast and play the game rather than having a laugh with your team, and even if you are excellent at it maintaining that focus at speed for hours at a time will utterly drain you.
If I have a day with a lot of this I will come home absolutely, brain dead shattered.
I do it because people are important and I do value them, but the aim is to get away from "I ask a thing, you ask a thing" and into "hey I read/saw/heard a thing I think will interest you" and "how's it going with that thing I know is important to you right now?"
So, when you get high and mighty about people being selfish for doing social chit chat the "wrong" way, remember what you are really asking is that they bend themselves out of shape to be a shape that you personally find more pleasing. Kind of selfish there as well, no?