Because this isn't actually a cognitive thing for you. Not yet, anyway. It is a need to be needed perhaps. Needed until someone recognizes your pain. People like the ones you are speaking of don't recognized other's pain as being anything type of gift of how hard you are attempting to please. They feel they deserve other people to feel pain for them. And the more the better. Until they break.now my cognition has been "fixed"
When that feeling comes along that says 'I need to give more' that is your cue that something is going on with you - that you can work on - so you don't keep getting trapped like this.
It is the gift that keeps on giving until we repair the wiring. Being raised by a narcissist is no joke.