One of my clients calls her habit of going to extremes, her “do-it-or-screw-it mentality.” My hunch is that you have a similar mindset that gets you into trouble in all sorts of ways. All-or-nothing thinking isn’t a permanent affliction, however. You can opt out.
Step 1 is to examine your behavior and assess (need I add, without judgment) whether you tend to think in either/or, full/empty, success/failure ways. Come up with examples and, if you determine this is your modus operandi, simply acknowledge the fact. If you start to get down on yourself for polarized thinking, resist, and take a long, slow, deep breath of self-compassion. You didn’t choose to go the all-or-nothing route; rather, you learned an ineffective way of thinking and behaving that you can change.
Step 2 is to explore how you developed this pattern. We learn from our early role models. Take a look at family members and identify parents and siblings who function on an either/or track. Look for rigidity and black/white, good/bad, rule-bound thinking.
Step 3 is to examine the beliefs under your all-or-nothing mindset. Are they valid? Is it true that if you don’t go to the gym today, you might as well give it up or that if you’re going to have a slice of chocolate cake, you must eat the whole thing? Recognize—and maybe have a little chuckle—over such pretzel illogic, then answer these questions: Who said this way of thinking and doing have to be? Does this pattern work for you? Why do you continue to do it? What stands in the way of not doing it? What would you gain by abolishing it? What would you be giving up? How would it feel to be more balanced and less extreme? What would it be like to enjoy more of a middle-ground?
Step 4 is to reframe your irrational beliefs to make them rational. For example, There’s a lot of ground between success and failure, I can find a middle position between all or nothing, I’m learning to value shades of gray and incremental thinking, I enjoy regulating myself. Step 5 is to list about a half-dozen or more instances where your polarized thinking plays out, eg, with food, exercise, doing tasks, friendships, work, play, self-care, TV, schoolwork. Then go through each example and write down a middle-ground: having some chips, going to the gym three days/week, visiting your parents several times a month not every week, staying late two nights at work rather than five, etc.
You can teach yourself to break your all-or-nothing thought and behavioral patterns. What you need for tools are awareness, motivation, and a new belief system.