Focusing on one subject!
When you exclusively focus on one subject, you may achieve what you want to achieve regarding that given subject and observe manifestations related to the subject you are focused on. However, it is strongly possible that you will remain veiled from other manifestations that related to other things in the meantime. Thus, you will overlook certain things.
Perfection entails evaluating every occurence and manifestation accurately and taking the right action accordingly.
Allah (ﷻ) knows best.
Ahmet Şahin Uçar