One of the laws of learning is that it requires repetition, drill, and a lot of practice. It takes as much time as it takes to learn a maneuver, and more time and practice to gain proficiency, yet there are some student pilots and CFIs who resist repetition, insisting that the maneuver has been learned and can be flown to standard after one lesson.
This is dubious at best, and can be an example of the Dunning-Kruger effect, a cognitive bias where people with limited competence in a particular domain—like flying—overestimate their abilities. It is particularly common with someone who took lessons in the past then returns to it decades later. It can be difficult to accept the fact there is some rust on those skills.
