I literally have the opposite problem with my mates. I feel that I'm two dinners in debt to them, but they'll still insist on getting the next one because I paid last time, or something.
My grandma used to say, “Always underpay or overpay a debt to friends”. It’s a way of keeping people in your life, keeping that obligation alive. Not in a manipulative way. Obviously you don’t want people talking to you out of pure obligation. Just more of a gesture indicating that we don’t plan to part ways forever.