You need to clean your apartment. You decide you are going to deep-clean the carpets, scrub the baseboards with a toothbrush, alphabetize your books, and reorganize the pantry. You calculate this will take 12 hours. Because you only have 2 hours of free time tonight, you decide it's not worth starting. Instead, you sit on the couch and watch YouTube, leaving the apartment exactly as messy as it was.
This is the ADHD All-or-Nothing Trap. It is frequently confused with clinical OCD or "Type-A" high-achiever perfectionism, but the mechanics are entirely different. An ADHD brain does not actually want the apartment to be perfect. The ADHD brain is deeply overwhelmed by the baseline executive function required to simply wash the dishes.
To justify its failure to wash the dishes, the brain creates an impossibly high standard. "Perfection" becomes a psychological shield. If you fail to meet an impossible standard, you protect your ego: "I didn't fail because I'm lazy; I just didn't have time to do it perfectly." The perfectionism is a hallucination designed to protect you from the intense vulnerability of starting a task and showing a flawed effort.
Coupled with Rejection Sensitive Dysphoria (the intense fear of criticism), the ADHD brain believes that delivering a "B-" effort is a catastrophic threat to your social and professional survival. Therefore, you do nothing. You must learn that in the neurotypical world, a "C+" project delivered on Tuesday is vastly superior to an "A+" project that exists only in your imagination.