To your statement lecky i have to say that both extreme ends are unhealthy narcissism: caring too little and caring too much. For example taking care of other persons emotional needs above yourself and extensively is narcissism, you don't recognize your limit's nor the other persons private area. You see...Like being a therapist to another person and attaching him/her this way to you. INFP know how people feel and that's base for manipulation.
Narcissism is not that simple term.
I dont know are these issues only common in INFP's, but like you can see above, my biggest problems have been several mental disorders: borderline personality disorder, narcissm, ptsd, depression, anxiety, social anxiety disorder, panic attacks, bipolar and so forth. My head drives me crazy.