Even the best teachers are not perfect. Thinking back to my own experience with my previous teachers, I realize that some of them had a bad day now and then. Or maybe I was the one having a bad day. In either case, it seems that most classrooms have some distractions* from time to time. Once I got "off track" during a lesson, it was really hard to catch up.
*Examples of distractions include situations where other students are moving or making noises, my own worries about friends or school, family concerns, being hungry, needing to go to the restroom, looking for a pen or pencil, or needing to sharpen a pencil, etc. There are many sources of distraction. Even "fear of failure" can be a distraction!
During those distracting moments, we probably missed out on some element of a lesson, and that created a GAP--maybe a critical missing piece of our learning process. One of the goals of working with a tutor is to fill in those gaps, so we can do our best in the future. Sometimes it only takes a lesson or two. Filling in some gaps can build confidence, bring relief from "test anxiety" headaches, and allow us to succeed in subjects that we used to find difficult.