People need each other, for basic reasons. Root reasons. Primal reasons.
Most basically, we need each other for survival. This, no doubt, originated with ancient humans standing back-to-back and fighting off beasts with nine-inch teeth. Then, talents were discovered and someone took the role of hunter; another, the cook; another, the healer, and so on... We still operate that way.
Less basically, while the hunters were out looking for wild Whateverbeast, they got to talking (or grunting) and then one slipped on a paleo-peel of some kind and they cracked up about it, and "the friendship" was born. And that night, as the tribe sat around the fire, gnawing the last of the goodness off of the Whateverbeast bones, a man connected eyes with a woman and he offered her the last of his marrow and romance was born...
Everything spiralled off of these things, right? Necessity became safety; safety became comfort; comfort became "society."
This part of it, I get. (At least, I think so -- you tell me what you think.)