Eid-ul-Fitr is the only occasion where Allah tells us to rejoice and celebrate for revelation of the Qur'an in Ramadhan.
Eid-ul-Fitr = JASHN E NUZOOL E QUR'AN
10:57 O Mankind! There has now come to you Enlightenment from your Lord, and a healing for all that troubles your hearts; and guidance and grace to all who embrace it.
10:58 Say, “In this bounty of God and in His grace – in this, then, let them rejoice. It is better than all the treasures that they may amass.”