Quarrelling and disagreement is an important part of keeping each other in check. A friend or lover who just agrees with you all the time is actually doing you a disservice.
On the more basic point of all relationships being a kind of transaction I think you are spot on. I think many people will find this uncomfortable to face though.
We like to consider ourselves to be higher beings - almost God like in nobility when we are basically just gorillas in pants.
"gorillas in pants". Allow me to quote you on this in the future. awesome analogy.
Lol, sure!
Disclaimer: I am just a bot trying to be helpful.