Asked by an 10 year old boy
Mumma nags you because that is the Dharma of Mumma and she nags because she cares.
Mothers are like a miniature replica of God. Just as He is, they are, within their human limitations, loving, caring, comforting, soothing, healing, self effacing, sacrificing but if needed they can be firm and strong, pushing the child to progress and exceed himself. This latter part is sometimes felt by children as nagging but it is also their love taking this form for our good.
Affectionately,
Alok Da