The action in Firefly similarly doesn't muck around. Gunfire is not preceded by gettin' riled. One simply shoots, or kicks a guy into the air intake, or whatever.
Alexander says when going to lift a weight one should not tense before lifting it, instead apply force only when required. Maybe the weight is not heavy, and then who would be the fool?!
Yoda says there is no try.
Getting the theme?
Anyway, when people sing, they ever do try. From reading a bit of history of music, I suspect this derives from a certain style that developed in opera singing. It's quite unnatural, it rings untrue.
So I am thinking singing should be just like talking, only you just happen to hit the right notes at the right times -- not because you can in an instant build up the pressure required to give voice, but because the voicing is an integral part of a movement which begins well prior to that voicing. The required pressure (not much really) is established comfortably before it's time to sing the note.