Margen
Three euros for the coffee, two for the app you no longer use, four for the impulse buy in the checkout line. None of them hurts. But three euros a day is nearly 1,100 € a year: ant-sized spending doesn't ruin you by size, it ruins you by frequency and invisibility.
The experiment that exposes it costs one month: write down every small expense, without judging yourself, just watching. Most people discover two or three leaks they never consciously chose: dormant subscriptions, fees, boredom purchases.
And here's the important nuance: the solution isn't to forbid yourself small pleasures, it's to choose them. The coffee with your coworker can be worth every cent; the subscription you don't even remember, not so much. Ants aren't exterminated: they're taken through roll call.