This is a good video! It's true that strict self criticism seems to make improvements. It's possible that the artist mentioned could sense something was off without knowing the logic in how to fix it. I've heard once that an artist's skills don't all 'level up' at the same time, that your eyes could be better at feeling out what to do before your technical skill has caught up with it. Thinking like that has helped me not get overwhelmed with negative self criticism... This video reminds me of that fact, good job.