Consider the following statistic: In countries where organ donation is the default selection (also known as “opt-out”), more than 90 percent of people register to donate their organs. Compare this to countries with an “opt-in” policy, where fewer than 15 percent donate.42 A default “opt-out” is powerful because people typically follow the path of least resistance and stick to the status quo. So take advantage by calendaring the most critical things in your life as opt-out: calling your family, focusing on deep work, exercising, etc. You can always opt-out, but you’ll be more likely to stick with the default—your desired behavior.
Source: Ben Meer