If you can cultivate wholesome mental states prior to sleep and allow them to continue right into sleep without getting distracted, then sleep itself becomes wholesome.
Dalai LamaOnce we have a firm practice of compassion our state of mind becomes stronger which leads to inner peace, giving rise to self-confidence, which reduces fear. This makes for constructive members of the community. Self-centredness on the other hand leads to distance, suspicion, mistrust and loneliness, with unhappiness as the result.
Dalai Lama