Ibn Abbas (radi Allahu anhu) narrated that the Prophet (sal Allahu alaihi wa sallam) said: “The pious offspring who casts a single look of affection at his parents receives a reward from Allah equal to the reward of an accepted Hajj.” The people enquired: “O Prophet of Allah (sal Allahu alaihi wa sallam), if someone casts a hundred such glances of love and affection at his parents, what then?” The Prophet (sal Allahu alaihi wa sallam) said: “Yes, indeed, even if one does so a hundred times a day, he will get a hundred fold reward. Allah is far greater than you imagine and is completely free from petty narrow mindedness.” [Sahih Muslim]
Love your parents and consider this act as a privilege and a source of reward in the eternal world. How much parents love their children, how much they happily sacrifice for them, and how much they want their child to be more privileged than they are, can only be understood when a person becomes a parent themself. Nobody likes to see others get ahead of him/her in this world except parents, who love to see their children better off than them in every way and for this they willingly sacrifice whatever they have.
Allah is the only one who really knows what is inside a parent’s heart. In order to help us to acknowledge and be grateful for their love Allah (subhana wa ta’ala) gives us mountains of reward from Himself for loving our parents. Truly, no-one is as appreciative as Allah of the love that parents shower on their children.
Should a person look at his/her parents lovingly even a hundred times a day, Allah (subhana wa ta’ala) will give them the reward of a hundred accepted Hajjs. There is no scarcity with Him. He needs to set no quotas on how much reward a person may earn in a day. It is humans who are petty and stingy towards each other.