I've been asked by Haven to write a bit on my own experience with BPD and empathy. Before my BPD diagnosis I knew I was highly sensitive, the more official name for that being Sensory Processing Sensitivity and it's there in about 15-20% of the human population, and even exists in other animals. As you can guess, people who experience the world with heightened sensitivity are very liable to fall victim to various psychiatric conditions, such as depression, strong mood disturbances and mood fluctuations, PTSD and general dissociative conditions. It's almost part and parcel of being HSP, given all the normal challenges we encounter every day in our lives.
One of the defining features of being an HSP (Highly Sensitive Person), is having strong empathy; The ability to literally feel someone's else's emotions, to inhabit their world, momentarily and to transpose our own happiness, insecurities and pain from the other person's experience. This often leads to an over-projection, where we forget the other person may be much thicker skinned, much less affected by emotions than ourselves, or it may just be that we recognize the strength and significance of someone else's emotion before they even do. Who knows.
It can mean we feel close to people who we barely know, and other people are drawn to the fact that someone they hardly know, feels so familiar to them.
BPD I'd say is just when sensitivity has detrimental effects on our health and relationships. I'm classified on the lower end of BPD and I wouldn't even begin to say my experience of it is the same as other people's. At the end of the day, regardless what we label ourselves or have been diagnosed with, the behaviours look the same, and it's the behaviours that matter, not the label.
In relationships, I've been called everything from perfect to selfish, cold and a psycho bitch among other things. So, from the outside looking in, I guess, I'm not always an angel. If I was a doormat I wouldn't survive, quite literally, so I'm very glad I'm not. There are some exes I'll always be fond of, even those who hurt me in some way, I just can't always shake my empathy/sympathy and affection for them, even though I have to protect myself and accept the reality of a doomed relationship.