Imam Hassan (as) was listening to her mother praying at night. All night, the daughter of the Prophet (pbuh&hf), prayed for other Muslims not for herself.
It was Thursday night. The mother was facing the Kaaba, praying to her Lord, while her little son sat beside her, listening carefully. In spite of his age he watched every movement of his mother, standing, bending, prostrating. He heard her pray for every Muslim man and woman they knew. She prayed that they be blessed with honour, contentment, goodness and piety. Now he wanted to hear what she would ask for herself.
He kept awake for as long as she prayed, only to learn what she would ask for herself. The night passed and the new day dawned. Imam Hasan (as) asked his mother, Lady Fatimah Zahra (as), why she did not pray for herself but kept praying for others all night.
His mother answered, "My dear Son! First think about your neighbor, then think about yourself."
Reference: Bihar al-Anwar, vol. 10, p. 25.