I hear you there. In high school I struggled so much with "How are ya?" As a depressed person living in my head with a huge amount of anxiety, the true answer to that question involved minutes of conversation. Knowing that nobody wanted those minutes still took me several seconds to blast over and discard, then trip and stumble through an answer before landing on something. It took a lot of work to just be able to say "good", even when that wasn't the true answer, or even an appropriate response to the question asked. They are just simply social barks of no meaning.
It was a long time coming before I realize what you said above, that most of the time people aren't in the mood to engage their brains and have a serious discussion right as soon as you meet up, that you have to work up to that kind of thing.
In terms of learning, I've always been of the mind that you have to keep the difficulty proportional to the skill. I game a lot so they are useful analogies for me, but when teaching someone, you can't throw them in against a professional player and expect growth, you have to first teach the person to be average level and familiar before time with excellent players is beneficial in the slightest.
Ironically, middle and high school is probably some of the most treacherous and brutal social situations we all have to go through, and at a time when we are all weakest at doing so. Interacting with most sane adults is generally the best practice before people get thrown to the lions, but that never seems to be the way it goes.
In some ways I wonder that its generally easier to interact with adults because we have all been mostly scarred at one point or another in high school, and thus learn empathy properly, but eh.