So you're listening to a shmaltzy power ballad because it's the only kind of music you can cope with since you were dumped by your girlfriend / husband / android concubine.
The song starts with a quiet intent; nothing too fussy, just a clear melody and a trusty verse / chorus structure. The rhythm section beefs up at the start of the second verse, and swooping backing vocals in the second chorus signal that this is building up for something quite specatular.
The middle eight is a teaser. Often neglected and ropy, this turns out to be a bridge into a penultimate chorus that is sung with gusto and a tinkling of extra keyboard.
You're in the zone now. That bitch / doormat / electronic succubus can get screwed. You're an independent ballad-listener and you can lift your head high as the melody soars and your heart strings wobble.
What happens next? You know what happens next
It's the key change. The final chorus steps up a pitch, and all the extra black notes are a delight.
The key change is the sonic equivalent of that last-minute sprint, of that second wind after the sixth pint, of that moment of lucidity when you realise that yes your life is going nowhere and yes you're going to tell your boss to stick his job up his pipehole.
The key change is cheesy elation.
Which leads me to my question. Why doesn't the key change ever go downwards? And what would be the effect on those plucky heartstrings?
If the famous ballad key change went down instead of up, that last minute sprint would be an exhausted tailing off, leaving you gasping and retching at the finish line.
It would be like a shot of heroin and a long evening spent crying in the corner: a cloying realisation that there is nothing you can do about life; it inevitably ends in disappointment, rejection, and your boss sticking his pipe up your arse.
The middle eight was a teaser, but if the key change suddenly slips downwards, life would not be worth living any more. It would break all pop song convention. I will not always love you. Shmaltzy power ballads would become synonymous with anti-climax and diazepam.
Crikes, I'm depressed just thinking about it. I'm sure there are many songs that finish with a downward flourish, but I can't think of any and, to be frank, I plead with you not to suggest any. I don't think I could cope.
That android concubine was a no-good loser anyway. You're better off alone.