I only followed the first few posts in this thread. I recommend reading
"Why Man Needs Approval" Marsha Familaro Enright (_Objectivity_ 1(2)).
Sadly, this essay has not been placed on the web. (_Objectivity_'s web page is at http://www.bomis.com/objectivity/.)
Anyway, to some extent, what Enright believes seems to be that friends and lovers in a sense make our lives fuller because they satisfy a basic need for self-perception. I.e., we see ourselves through others -- in much the same way that we need a mirror to see our faces.
Why is self-perception of this sort necessary? If my memory's correct, it's because we need to be able to experience our achievements (personality-wise) in a full way -- a way we can't given that we're always on the inside looking out. In a lot of ways, this is very Hegelian, though the point Enright is making is psychological NOT ontological.
Ergo, from a transhumanist perspective, we might ask, do we need this aspect of our psychology? If we don't, can we edit it out? If we do, how can we refine or fit it into what we wish to and will become?