Ash-Shaykh Muhammad bin Saalih al-Uthaymeen, rahimahullah, said:
As for showing happiness and joy on Eid al-Fitr and Eid Al-Adha, there is nothing wrong with it as long as it is within the boundaries of the religion. From the means of that [showing joy] is bringing the people food and drinks and that which is similar to that for it has been authenticated that the Prophet (peace be upon him) said,
“The days of al-Tashreeq are the days of eating, drinking and remembering Allaah.”
What is intended by that is the 3 days after the noble Eid Al-Adha for verily the people sacrifice and eat from what they have sacrificed and enjoy the blessings of Allah upon them. Likewise during Eid al-Fitr there is nothing wrong with showing happiness and joy as long it does not trespass the boundaries of the religion.
Abu Aisha Yasin