I can play 6 hymns on the piano. I can play them well and I often trick people into thinking I am a regular pianist. But as soon as they ask me to step outside of my happy 6-hymn-repertoire, I say no way, jose. But I don't mean to be rude when I say no way jose -- it's just that I can't, Jose. Can we still be amigos?
Back when I was 15ish, I volunteered to play the piano for opening exercises of Wednesday night mutual. I had learned to play "Called to Serve" from the Hymns Made Easy songbook and I had become pretty good at playing it by myself.
What I didn't realize was that playing the piano by yourself and playing it with people singing was 2 different experiences. Very very different.
Nonetheless, I sat myself down at the piano and began to play. As people began to sing along, I choked. My fingers just couldn't seem to find the right keys. I didn't give up though. My brain went into panic mode and I just began pushing any button that looked appealing. This ended up not sounding at all like "Called to Serve" from Hymns Made Easy, but more like a bad version of a John Cage arrangement.
The sing-alongers became confused and weren't sure if they should continue in their quest to sing "Called to Serve." But they plowed on anyway, shooting me sideways looks wondering if they should call for help.
So there we were, I was having epileptic panic spasms at the piano producing the occasional note and the singers were torn between their desire to sing a hymn in reverence to the divine and their fear that my piano-induced rage may be putting them in danger.
One girl, Ashley, started laughing at me. She laughed and laughed. Turns out she had asthma and her laughing fit turned into an asthma attack and she had to go home.
Now I'm very careful about when I play piano for hymn-singing. It can be very dangerous.