There's an old saying that nothing good happens fast. I don't know if that's altogether true, but it does have some bearing on Bible study.
Teaching that impacts is not head to head, but heart to heart.
If you are not thinking correctly, you are not living correctly. What you believe will determine how you behave.
Jesus never discipled one-on-one.
The teacher has not taught until the student has learned.
Nothing is more common than unfulfilled potential.