I hope you don't mind this (if you do get a moderator to delete or merge the thread) but I really wanted to give some input on this discussion, but it's in a private section. I have a friend who I think is an INFP and I think I've noticed how this works in her.
I don't think INFPs necessarily have this trait, which is traditionally more Fe, but it all depends. I think if one of an INFPs main values is the peace and the happiness of others (which it often is), this can lead them to behave in a manner similar to Fe, where they try to achieve their values by helping people and if they fail to create happiness, they have failed in this value and often feel guilty about it. I have noticed this in her attitude, but a major difference is that I think INFPs tend to be less situation based in their pleasing of others. They are likely to have a desire to create happiness and harmony, but will sometimes go against this when it contradicts their other values, and look in a more big-picture sort of way to achieve this rather than in individual situations.
This is my take on this from experience, but please correct me if you find it different.