Superhuman by Habit: A Guide to Becoming the Best Possible Version of Yourself, One Tiny Habit at a Time

Second, you should be very scared to fail to execute a habit, even once. By failing to execute, potentially you're not just losing a minor bit of progress, but rather threatening the cumulative benefits you'd accrue  by establishing a habit. This is a huge deal and should not be treated lightly. So make your habits relatively easy, but never miss doing them.