Reciprocation

Isn't it selfish, how reciprocation is often treated as an obligation? And the deficiency of it somehow ends up as a fault, as though non-compliance is unethical. It's like buying someone coffee, and then expecting the other party to join you for coffee dates every other week. I'm not saying you shouldn't be grateful for free coffee, but why do I feel like I have "ungrateful, arrogant cunt" stamped on my back when I refuse for more coffee? I mean, I don't know man. Some people like me just don't like coffee... or the person who bought it...