Empathy is the capacity to imagine how another person feels. Empathy is learned experientially. In other words, the way we learn to be empathic is by being empathized with. This must come early during infancy and toddlerhood. When we cry, the hope is that there is a consistent warm empathic response from a steady primary attachment figure, usually the mother.
People who are narcissistic, or have narcissistic traits, are missing the computer chip in their organized personalities to empathize with others. The reason empathy is a valued trait is that without it most relationships risk collapse. It is human nature to long to feel seen, validated, understood, and accepted. Without empathy this cannot occur.