Despite the fact that I don’t think of myself as any kind of musician, I am constantly creating musical pieces in my head. Most of the time, those ideas fade away into a deserved oblivion (because they are bad ideas). Sometimes, they stick.
Recently, I sat down at the out-of-tune piano in our house and played a few chords. I quickly came up with verse and chorus parts, and almost immediately envisioned the complete song in my head.