The practice of metta is powerful and challenging because it works on so many levels - the personal, the relative and the transcendent. Opening to all these levels and being willing to work with whatever arises makes this practice deeply transformative.
Learning how to work skillfully with the pleasant experiences that arise from the development of metta and concentration is an important part of supporting the deepening of these practices.
When we see the world through the veil of our ego, our love flows in distorted and confused ways. Through mindfulness and metta and insight we can begin to understand these conditioned patterns and transform them into love and connection.