Some people are born with a great gift for love, while others have to learn love from the very basics—possibly by expanding self-love into love for others.
For others yet, love is a very difficult exercise, and in order to achieve it, even to the smallest degree, they have to make deep structural personality changes.
Some people experience love only for a fleeting moment.
Only a few–possibly, those who have this gift from birth–are willing, and able, to attain totally unconditional love.
–Rabbi Adin Steinsaltz
From Simple Words, p. 200, by Rabbi Adin Steinsaltz