Perfect love is rare indeed - for to be a lover will require that you continually have the subtlety of the very wise, the flexibility of the child, the sensitivity of the artist, the understanding of the philosopher, the acceptance of the saint, the tolerance of the scholar and the fortitude of the certain.
It is highly significant, and indeed almost a rule, that moral courage has its source in identification through one's own sensitivity with the suffering of one's fellow human beings.
Lack of sensitivity is perhaps basically an unawareness of ourselves.