For what? You didn't do anything wrong.
I'm sorry because you get hurt because of me. Whenever I made a mistake, you're always there to erase it. But as you make my mistakes vanish, you lose a part of yourself. You get smaller and smaller each time.
That's true. But I don't really mind. You see, I was made to do this. I was made to help you whenever you do something wrong. Even though one day, I know I'll be gone and you'll replace me with a new one, I'm actually happy with my job. So please, stop worrying. I hate seeing you sad.
LESSON: Parents are like the eraser whereas their children are the pencil. They're always there for their children, cleaning up their mistakes. Sometimes along the way, they get hurt, and become smaller / older, and eventually pass on. Though their children will eventually find someone new (spouse), but parents are still happy with what they do for their children, and will always hate seeing their precious ones worrying, or sad….However our parents are getting smaller and smaller each day…One day, all that we would be left with will be eraser shavings and memories of what we used to have.
Allah, Most Wise admonishes us: "Thy Lord hath decreed that ye worship none but Him, and that ye be kind to parents. Whether one or both of them attain old age in thy life, say not to them a word of contempt, nor repel them, but address them in terms of honour. And, out of kindness, lower to them the wing of humility, and say: My Lord! Bestow on them thy Mercy even as they cherished me in childhood." (Quran-17:23)