People pretend to be friends for mating or monetary advantage, or to use them as a backup emergency. All the relationships are only justification and denial as no person can believe they would use other people – so they don’t believe it. Having neighbors who can help you out of a jam, that is just a loan when they help you, to return and ask for a bigger favor later. People are not all calculating masterminds but the realities of life lead the same pattern to show over and over.
A working marriage is ultimately a business enterprise. The veneer of love falls away.
It’s all a survival trait. We believe we lived in a civilized society but it’s a facade when you consider nobody is helping anybody from the kindness of their heart. They are doing it for likes, hearts, thumbs up, and money.