I have worked in HR for about 15 yrs and have interviewed a lot of candidates. I would recommend staying away from the “I’m a perfectionist” answer or disclosing that you have ADHD during an interview. What I would suggest is having an answer to this question prepared beforehand so you are not caught off guard during an interview. A good way to do this is to go through the job description and pick a skill or duty that you do not have much experience with and give the interviewer concrete examples about how you are working to improve this skill. This approach shows the interviewer that you have an understanding of the job and how you will own your professional development in an area that is not your strong suit.