When Practice Becomes Frustrating
The Buddha's teaching is "good in the beginning, good in the middle, and good in the end." As one practices the Noble Eightfold Path, the mind becomes increasingly peaceful and happy, ultimately culminating in the complete cessation of suffering through the realization of liberation and Nibbana.
Whenever you find that your mind has lost its peace, it is worthwhile to examine the five hindrances. In many cases, one or more of them will be present.
One subtle hindrance is craving for attainment. Instead of abandoning craving, the practitioner simply replaces the desire for worldly pleasures with the desire to attain liberation and Nibbana. Although the object of craving has changed, the underlying craving remains.
The aspiration to practice is wholesome, but craving for attainment becomes another obstacle. Liberation is not realized by craving for liberation and Nibbana, but by understanding and abandoning craving itself.