Sometimes devotees are very enthusiastic when they are in the physical presence of guru, but when he leaves, then somehow that enthusiasm and steadiness dissipates. Steadiness comes from the following: faith, chanting, hearing Krishna-katha, devotion, inspiration, discipline, the desire to please the guru, and understanding and serving the internal mood of the spiritual master.
Lectures from a Disciple, "Serving the Mood and Instructions of the Spiritual Master", Pg 317,1st Paragraph