Amazon has a type of checkout, called 1-click, where you can complete the entire checkout process (specify the payment method, confirm the shipping address, select the delivery preference, etc…) just by clicking one button on the item page. By default, this setting is OFF. The flow they have to turn on this setting is a bit abrupt.
On the right hand side in the image above (highlights added by me), there is a secondary call to action underneath Add to Cart that states Sign in to turn on 1-Click ordering. Here’s what happens if you click on this link. First you see the sign-in page:
No surprise here. After signing in, you see this:
A confirmation page telling you that you have now signed up for 1-click. What happened?!? As a user, my expectation was to be taken to a settings page where I could check a checkbox, or toggle a radio button, or click a button to turn ON 1-click. As a general pattern, it is a bit odd for a user to see a confirmation page of any kind after signing into a site. Typically, you want to have the user sign-in, be verified, and then click on a final confirmation call to action to finish the flow. To have it occur immediately after the sign-in page was a bit abrupt.
For example, the user can be taken to a page that looks something like this where they could then confirm their decision.