All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
Indeed the right of the parents and grandparents is great. Islam forbids saying "Ouf" (a word of disrespect) to ones parents. Allah Says (what means): {… say not to them [so much as], "uff," and do not repel them but speak to them a noble word.} [Quran 17: 23]
So, the child should not do or say anything that could make one of his parents or grandparents angry.
So, you should respect them, do your best to please them and never harm them. Always remember the Anger of Allah and beware of making them angry.
Allah knows best.