More from Dietrich Bonhoeffer:
Repeatedly, there will be times when we feel a great spiritual dryness and apathy, an aversion, even an inability to meditate. We dare not be balked by such experiences. Above all, we must not allow them to keep us from adhering to our meditation period with great patience and fidelity.
It is, therefore, not good for us to take too seriously the many untoward experiences we have with ourselves in meditation. It is here that our old vanity and our illicit claims upon God may creep in by a pious detour, as if it were our right to have nothing but elevating and fruitful experiences, and as if the discovery of our own inner poverty were quite below our dignity.
From Life Together, "The Day Alone", pp 83-84.