I mean to say that good singing and thinking really don’t go together. Someone (? needs attribution!) has done functional MRIs or scans or something of people while they’re singing and has discovered that the cognitive area of the brain is, for the most part, not engaged.
But even without that non-attributed, perhaps completely made up, “scientific fact,” I can tell you from experience that I think a lot when I talk, and I sing well when I don't.
I’ve come to feel that singing is much more like weight-lifting than it is reciting a poem with notes. Songs turn out better when I stay in my body, when I notice how the song physically feels as it’s happening. Turning on the thinking brain seems to turn off the instrument.
Put another way, the audience doesn't need my Deep Thinking, they need me to give them something to listen to. They need me to breathe in, deep and low, and then make an efficient, beautiful tone. Breath in, tone out, stay out of the way. As attached as I am to my thoughts and reflections, at the moment of singing, they're the last thing that's needed.
It has taken me years to learn this.