> Sometimes I feel that it can be a lucrative trap to become invested in a single person, and then accumulate expectations that far outweigh the responsible obligations of any friendship.

Lately I feel like this about traditional romantic relationships as well. After a while many people start developing expectations of the other person and assume that they will or can meet all of your needs, when that's actually pretty unrealistic. I was in a six year relationship when I noticed that my partner wasn't meeting my needs anymore, and that my expectations of him which had grown over the years weren't really aligned with a healthy reality; this applied the other way around as well in terms of my partner's expectations of me as a person who's changed over the years. I recently left the relationship and am now re-examining my own outlook on the traditional relationship models.