In our day to day, we’re involved in thousands of micro transactions. As a lazy species, we would always like life to go as uninterrupted and flowing as it may. I can give a late new regulation in Israel as an example — it is now mandatory for supermarkets to charge 10 cents on every plastic bag you use to take groceries home. When the legislator came up with this bright idea, he was probably saying “Well 10 cents are really not much”. Yet the mental transaction cost involved is quite high — You already pay for the groceries, so now you need to pack them all up in an unknown amount of plastic bags, only then you know how many bags you might take, you need to reach out again for your wallet and look for the exact amount of cents, which you probably don’t have, so you need to pay and get change from the cashier again. It’s a quite cumbersome process that personally annoys me a lot. One conclusion Szabo reaches is that while smart contracts enable us to pay different and changing small amounts according to our transactions, it might just be that a subscription model with constant pricing of some kind would better fit our desire of reducing mental transaction costs.