Breaking The Cruel Instinct
When we give tzedaka, the main task is to break our instinct to be cruel and turn it in to lovingkindness in order to give generously. When a person who is kind by nature gives charity purely out of instinct, it cannot be called an act of service of Hashem. In order to fulfill the mitzvah of tzedaka in the proper way, one must first experience the battle of breaking his natural instinct to be cruel and turn it into love in order to give to tzedaka.
(Rebbe Nachman of Breslov)