I think I'd mostly like to know about facial expressions and body language. I don't know either of these things and I sometimes worry about if I come off as a bit of a jerk to people because I don't interpret body language correctly, so I might take something they say at face value, but really, they're saying the opposite, or some other misunderstanding. Like if someone is sad and I ask, "Do you want to talk about it?" and they say, "No," but they're really actually saying with their body language and facial expression that they do want to talk about it, but I say, "Okay," and walk away, because I would totally do that.
I also don't understand why it's appropriate for someone to say, "How are you?" back when someone says, "Hi, how are you?" but the person almost never says anything after I ask that. That makes me feel awkward, like I shouldn't say it, but then when I don't say it, I feel like I'm being rude. Which one should I do?