Often learners will begin a new undertaking with low confidence and this will show in their posture and technique. As a coach, or teacher or any kind of mentor, it's important to understand that in order for a student to progress, they must be encouraged to unapologetically be themselves. This process begins by creating an atmosphere of safety and encouragement where learners feel they can challenge themselves.
This is a problem that does not affect everyone, but as a coach it's important that you teach to the student needs. If you fail to create an atmosphere where students can grow into their confidence, the result is a self selecting process, where less confident learners drop out, and whilst as coaches we can't always help everyone, if we have a pattern of people dropping out then it becomes a failure of our coaching that we have to reflect on and improve.