I used to be far more sensitive than I am now, or perhaps I've just adapted to it. When really young, I preferred being alone or with other kids to being with adults; their emotions were too complicated and large for me to understand, and so I was just left with this huge wall of feeling that I couldn't cope with and would eventually internalize. Kids were much easier and simpler. To this day I can not and will not tolerate being around a person who takes their emotions out on others, and if I have to, I am incredibly quick to tell them, do not take your shit out on me, I have nothing to do with it. I also cannot handle toxic situations for long, and will leave a job or relationship very quickly if the people involved can't deal with their emotions in a healthy way.
On the other hand, when it comes to personal relationships, I tend to be incredibly thick, never knowing or realizing someone is interested in me unless they actually say it. I think that's to compensate for the fact that so often people SAY one thing and DO something else. For me, if I feel something, I react in what I feel is a very predictable manner. Many times others don't, though. It made absolutely no sense to me, how they could shut their emotions down like that, and why they would want to. I still wonder, but now I just accept it and realize that if they are so unrealized, I don't really want them around me.