The mussar teachings tell us that the most important aspect of loving-kindness is not what you feel, but rather what you do.

Our most valuable acts of loving-kindness take place when we overcome an inner resistance, and do the benevolent thing anyway.  It has long been understood that the heart follows the deed – do good for people, and in time your own heart is transformed into a vessel of unalloyed kindness.  The other benefits, and so do we! ~ Alan Morinis