People are complacent in their own suffering

So im gonna be so fucking honest rn Ive dealt with so many incompetent people who only want to succumb to their sadness and its fucking weird. Why do you feel so comfortable In being miserable and terrible to be around. This thought sparked into my head awhile ago and its just been on my mind recently. So I dated this girl around 6-7 months ago now, for almost a year. And she was the type of person who would be neglectful to her own sense of self, she sunk so deep in this ideology that "Nothing will ever be better, nothing will ever get better; So what's the point to trying to be better." I understood this when I entered that relationship with her, but it still doesn't change the fact that she never tried to do anything. She lived with BPD and a multitude of other mental illnesses(all of which she was medicated for) and I have no problem with that but its just like she wallowed in this mindset that nothing ever happens and nothing will change. Its just kind of frustrating because I tried so hard to help her, I'm not even saying I'm this magical remedy because that would just be kind of weird.