Defaults are powerful. What we do without thought is what we'll do the majority of the time, shaping us more than anyone else can or any conscious action we can take. A helpful default behavior can protect us and encourage steady growth over time. Whether you're aware of it or not, negative defaults will always sabotage progress.
Defaults behaviors are impacted most by your environment. The ideal environment is designed so that the only possibility is the behavior you actually want. Trying to make change solely with willpower—trying to make yourself walk past the Chocolate-Coated Sugar Bombs in the pantry to get to the eggs every single morning, rather than just getting rid of the sugary cereal—without first changing your environment is a recipe for failure. As much as possible, remove even the option of the choice you've chosen not to make.
When you are faced with a decision that you can't entirely control, better choices come from having default heuristics or clear rules. Without some system for choosing, decision fatigue can lead to poor choices, but training yourself into the habit of only choosing based on one or two criteria can save precious willpower. If you have filters that help you choose quickly, you have plenty of willpower left over to make considered choices when there is no clear best option.
Learn how to identify, understand, and rewire your default behaviors and patterns and you will discover your optimal method for limiting self-sabotage, maintaining momentum, and reaching your goals in any area of life.