What is the importance of interpersonal relationships?

Humans are generally gregarious creatures, even the introverted ones, and so all benefit from haveing healthy relationships; consider a few reasons why-

People can be viewed as resources. For example, if you're in a tough situation and need assistance, the more friends you have, the more likely it is that you will recieve the help you need. Relationships increase opportunity for personal advancement as well, whether in a social setting, or secular. Anthropologically speaking interpersonal relationships were vital for our species survival some 11000 years ago when we were making the transition from hunter/gatherers, to farmers cultivating land. With the advent of agroculture a need arose to gather people together to maintain land for a common interest.