There were seven of us at dinner. The bill came and someone had already opened Splitwise. £26.71 each. The request arrived before I'd put my coat on. Not rounded. Not "call it twenty-seven." £26.71. I paid it standing at the bus stop. Somewhere between the main course and the bus, dinner became an invoice.
What's the smallest amount you've ever requested from a friend? Think about it. £8? £4.30 for a coffee? There's a number below which you'd feel embarrassed to send a request, and that number is lower than it used to be. It keeps dropping. That's the interesting thing. Not that we split bills — people have always split bills — but that the threshold of what's worth calculating has collapsed. We used to round. Now we calculate. And the difference between rounding and calculating is the difference between a friendship and an arrangement.
When everyone carried cash, settling up was physical and imprecise. Someone would throw in a twenty and say "that should cover it" and it wouldn't, quite, but someone else would throw in too much and the table would absorb the difference. Nobody tracked it. The imbalance was the point. You'd owe someone a vague, unquantified debt — not money, really, but a reason to show up next time. Marcel Mauss called this the obligation to reciprocate: the unresolved gift that binds people to a future encounter. Settle it precisely and you sever the thread. Leave it open and you've made a reason to return.
81% of people would rather be friends with someone who rounds than someone who pays the exact amount — even when the exact-payer contributes more money. We instinctively understand that precision between friends is a form of hostility. It says: I have calculated what I owe you and I owe you nothing further. There is no remainder. There is no next time.
During the First World War, the British government banned buying rounds in pubs. The No Treating Order, July 1916. They were worried about wartime productivity — too many workers showing up drunk. But think about what they were actually trying to legislate away: the ambient generosity of strangers buying each other drinks with no expectation of exact repayment. A government, during a war, identified imprecise social spending as a force powerful enough to regulate. The order lasted three years. It failed. You cannot outlaw the impulse to say "I'll get this one." You can only make an app that removes the need.
Cash made you feel the gesture. You watched the notes leave your hand. The pain of paying — the term behavioural economists use — was strongest with physical money. That pain is what made generosity legible. When you said "let me get this one" and handed over cash, the other person saw what it cost you. A Venmo notification carries no weight. It is the most frictionless way ever invented to tell someone you were thinking of them, and it communicates almost nothing.
The last time someone put their card down for the whole table without being asked, everyone went quiet for a second. Not because it was expensive. Because it was unexpected. That gesture used to be ordinary. Now it registers as a minor act of social courage. We didn't just lose the habit. We lost the context that made the habit unremarkable.
I still owe my friend James for a taxi in 2011. Neither of us remembers the amount. I think about it every time I see him, which means I think about him more often than I would if the debt were settled. Thirteen years of friendship, held in place partly by £14 that neither of us will ever collect.