When you write a song do you think its good to try something and sit back and think about how it fits and being careful about what you choose, or do you rather say "ohh that's not working, quick lets try something else" and get more ideas out there?
'thinking' about how it fits is a direct route to failure. songwriting only works when you are using your 'feelers'. One of the most common problems of songwriting is you get caught up thinking instead of feeling. and absolutely nothing good happens in that case