Some of my best songwriting choices started as mistakes or learning curves, when I accidentally hit a 'wrong' key or something. I try not to lose that the more I learn the how's and why's of piano.
Sentiment: POSITIVE
I've made a lot of mistakes and I don't regret any of them. Sometimes that's the only way you learn.
The joy of songwriting only gets messed up if you are trying to follow up a big success, or you are trying to create a hit single, or if you have conscious thoughts of a particular outcome for the music.