I had a lyric idea awhile back: "You/I got a heart but no brain... Lumber but no hammer/an apprentice with no master". (I haven't decided yet whether it will be in the first or second person). I then came up with some chords and a melody for it. But the melody and chords sounded familiar, and sure enough, I realized it was almost the same as another song someone else had written. I guess that song was in my subconscious. I was a little bummed because I couldn't use the melody and chords, they seemed perfect for the lyric. Not to mention that I would have to start over.
I have a bunch of music ideas without lyrics. I like to just fiddle around with the guitar and come up with music. When I get something interesting, I record it. So last night I started listening to some in hopes of finding one that might work for the lyric. After going throught the first 20 music ideas--not even half--I had 3 that might fit. So I went down to the basement and tried them out. One seemed to work the best. Interesting enough, it was in a minor key; the almost-stolen chords were in a major key. I actually like my chords and melody better than the one I almost stole!