Hmmm...I can and can't relate to both sides of this. I don't see myself in the descriptions of INFJs being so invested in helping other people that it becomes burdensome; this may sound selfish but myself comes first and I don't ever remember getting hints from anyone that I'm being too pushy. Maybe these INFJs are more extraverted than I?... Then I can also relate to not always being around, which is being attributed to INFPs. I just don't feel the need to always be connected to the people around me at all times. Sometimes I go into my "hole" and don't come out for a while and I'm sure this frustrates some people.
As for growth of self vs. growth of others, I think I focus on the former much more than the latter.