With thanks to Blaat for coming up with the idea
I also found it an interesting idea to explore, so in order to write something approaching a decent opening post, I went looking for inspiration on a dull Wednesday evening in front of the laptop. I ended up skimming through the "Laelius De Amicitia" written by Cicero around 44BC (because why not skim Roman philosophical texts right?!). You can find the whole thing here, but it's a long read. It's a dramatic account of Caius Laelius Sapiens talking of his life-long friendship to Scipio Africanus the Elder, roughly 120 years previously. I'll probably give it a proper read soon.
Anyhoo, Cicero generally talks about friendship in terms of it being a shared experience where both gain from one another, and share burdens. It's almost a symbiotic relationship.
I can get onboard with that as an idea, and it implies that a friendship which doesn't experience that equality of benefit isn't really a friendship.
That being the case I'd argue that I would end a friendship if I determined the friendship is inequal in benefit. I'd like to think I would do it if I was the one gaining more, but I'm honest enough to suspect I probably wouldn't.
But there are probably other reasons too. Politics, and religion tend to strain friendships. Maybe that is good enough reason for you?
So dear unwashed masses of NSG, go forth and discuss.
