A pessimistic take on this is that all relationships are transactional - basically the guilded age era of social darwinism but extended to all social interactions, not just economic.
An optimistic take is that humanity desires social interaction, and positive feedback is a motivation for engaging in polite and supportive social activity. You and others you interact with benefit from the positive feedback loop, so the chain reaction of kindness is incentivised for all those who desire it.
An analytical take is its impossible to find one theorem for all of humanity. Humanity is one massive unknown variable composed of billions of individual unknown variables, so it is foolish to try and derive one formula explaining the emotional reaction of love. How that may be triggered is just so unquantifiable at scale. The answer would be to simply embrace what works for you.
Not sure if any of these would be right.
Reminds me of Escape from Tarkov as well lol, need to add random Russian graffiti to the walls