Why we celebrate mothers day?

Because your mom has rights on you. See, mom's love is natural, she loves you whoever you are but we have to earn this love. Allah (God) said "And We have enjoined upon man[care] for his parents. His mothercarried him, [increasing her] in weakness upon weakness, and his weaning is in two years. Be grateful to Me and to your parents; to Me is the [final] destination.". Finally, Every day must be mother's day. <3

Mother foundation of society and this is the least thing to thank him...