Good further thoughts, valet. I like very much how simply Spielberg explains things.
I was thinking about that quote myself and, while I believe it's correct essentially, I think the other way that sentence could have been completed is this:
"And it’s amazing; [borderline people’s] ability to take care of someone else, to give the right answer of what you would do for that person, is very different from what they would do for themselves
or, in fact, for the person that they are in a relationship, most frequently"
Spielberg does address this in the 2nd of the two video clips; he talks about the tools he gives his patients to help them separate their emotions from rational thoughts.  :)BT strategies that we can all benefit from, I would say.
The point for me is that very often the knowledge of what the 'right' thing to do is there, but the overwhelming emotions make actioning that 'right' thing impossible.
People have often here asked questions along the lines of "are BPDs evil", "how can they be so cruel", "do they know their actions are wrong", "should we forgive them, if their actions seem immoral" - that kind of thing. I completely understand where these questions are coming from and the pain and confusion and anger that is often behind them.
There are moral/ethical questions here, most certainly, and it's fair enough to think in this realm. That sort of thing cycles back to other conversations on this forum and in the Resources about Personal Values and Boundaries etc. If we live in accord with that... .
I also kind of forgot now where I was going with this... .