Let me explain; in the episode something happens that upsets the oldest daughter, and she gets really mad, saying harsh things to her parents and lashing out at her little brother when she's messing with something. Later on in the episode, a guy (I believe someone who's famous) comes over and plays a song on a piano for the family. You can tell the oldest daughter is really touched by the song. When the song ends, the daughter breaks down and hugs her mom, saying "Mom, I'm sorry for the way I acted!" It was a touching moment. Anyone know which episode I'm talking about?

I'm not sure what episode you're talking about. The oldest daughter is named Mallory Keaton. Her younger brother is Andy. She also has an older brother Alex and a younger sister Jennifer. Her parents are Steven and Elyse.

What happens that upsets Mallory? So Mallory gets up set with Steven, Elyse and Andy? Then the guy you mentioned who is famous comes over and sings?

Can you remember any other details?