Recently, a dedicated Yogic scholar and practitioner shared with a group of us that what makes him the happiest now is to serve other people, not reading the classical Indian scriptures or chanting divine names. We could all feel his love. This is the highest expression of Bhakti Yoga and is fueled by the love and compassion that is generated by traditional devotional practices.
The core experience of Bhakti Yoga is that the essential nature of all reality is comprised of love, and love is what comprises the essential nature of God. The deep inner longing for oneness with the Divine is what propels and catalyzes the devotional practices of a Bhakti Yogi or Yogini. At the core of this longing is a sense of separateness from the Divine.