Looking on the internet deeply has found these results:

My dad is good at playing the piano is the most popular phrase on the web.

My dad is good at piano. 11 results on the web	My dad is good at playing the piano 14,760,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
That's why my dad is a hero. Look, my dad is the preacher round here. And my dad is definitely not interested. I'm not very good at the piano, but someone who IS good at the piano. My dad is Judd Ridge, Nashville legend. Yes, my dad is Hank. My dad is a PI I worked for him. He's not better than you at piano.	Come on, I know you're really good at your job, but I am really good at playing the game. You know, I'm pretty good at playing the odds. I know I'm not very good at playing the game. I hear you're good at playing the banjo. Because... You're... so good at playing the flute. She is good at playing the guitar. I'm not very good at the piano, but someone who IS good at the piano. And this is a young man who's really quite good at playing the guitar.

My dad is good at piano.

11 results on the web

My dad is good at playing the piano

14,760,000 results on the web

More popular!

Come on, I know you're really good at your job, but I am really good at playing the game.
You know, I'm pretty good at playing the odds.
I know I'm not very good at playing the game.
I hear you're good at playing the banjo.
Because... You're... so good at playing the flute.
She is good at playing the guitar.
I'm not very good at the piano, but someone who IS good at the piano.
And this is a young man who's really quite good at playing the guitar.