Do you think if enough people put in feedback that double tapping the side button on the Apple Watch would bring up Passbook instead of only the card you have assigned to Apple Pay then Apple would add this as an option? (BTW - I already did.) Surprised that Apple did not think to make this an option. Otherwise you have to go first to the home screen, then find the little Passbook icon, tap on it and then first select the card (either Apple Pay CC or your other cards like Starbucks, etc.) you want to use. Would think that this option would be rather easy to implement.