I should have been more clear in my original post -- the CHANGE from G (the last chord of the verse) to C (the first chord of the chorus) sounds completely different if there's a C in the verse than if there isn't. Obviously a C is always a C (assuming it's fingered identically), but the change to the C sounds different depending on what came before, even if what came before is several lines prior to the actual change.

And yes, Christopher, thanks, that's exactly what it is and foreshadowing in songs is a technique I use consciously all the time. I try not to have a brand new chord just appear in the middle of the song (with the exception of I, IV and V, which are fair game anywhere, IMO, whether they've been used before or not) without having foreshadowed it somewhere, otherwise it risks feeling disjointed.

So for example, if I'm going to use a minor chord in the bridge, I'll probably use it in the intro or in a turnaround so that it's not coming out of the blue when it appears "for real." So it's different, but different-good not different-where-the-hell-did-that-come-from.

But this is the first time I've been able to hear the tangible difference between when you foreshadow and when you don't. I guess I didn't realize that what I was already doing intuitively actually did have such a very specific impact, besides psychological, on the sound of the chord progression.