As a BPD sufferer I know that my emotions are often inappropriate. The most trivial thing can run me hot and cold. There's another monster inside me though. One that goes completely flat when others show emotion or something bad happens to someone else. 

There were two major events in my life where I was disturbed by my complete lack of emotion. The first one was when my grandmother died. I thought that the lack of emotion was due to shock and that perhaps once the reality of the situation had set in I would feel something. That never happened. I even recall feeling bored at her funeral. 

The second was when I essentially abandoned my husband for a coworker. I could see my husband's heart breaking in front of me but I felt nothing. I did feel guilty and uncomfortable but I felt no sadness whatsoever. I loved them both but I felt nothing for their loss or the loss of the people around me. I did cry over the loss of my ex-husband eventually when he started to cut contact with me but I was crying for my loss not for what I did to him or the pain I caused him. Is this a BPD thing or am I just a psychopath?