Whether it's actual time spent signing up, putting in my credit card data, updating expired cards, etc. Or linking my account/PayPal/Venmo to receive tiny transactions.
Or just the friction of "do I really want to pay $0.05 for this?" And I just don't want to make a choice, so I close the tab.
I know a lot of people dream about microtransactions changing everything... but even if they work flawlessly technically, I just don't want the mental overhead of making 20 tiny economic decisions every time I use the internet. Ugh.