Yeah I'm with you there, natural is best, you get to know whereyou need to breathe. I think we're singing off the same hymn sheet here, you call it training muscles up, I call it using a different voice to the talking voice ;). I have two or three different options, more in fact and none of them sound like me when I'm speaking naturally.

It's quite a bit to do with voice projection, we use our voices very differently when raising them or shouting, crying, moaning out loud etc, so when we project a singing voice it's going to lead us somewhere that is unfamiliar to anyone who hasn't really given singing a go. This at first feels a bit odd as in not the norm, some actually feel 'insincere' until they get comfortablle that it is their voice they're still using.

Not many people had voice training a 100yrs ago unless they were in choir, and a lot more people sang, being no TV etc.

That's a useful and new bit of information for me, the "nay nay naying". I sing mostly blues where you'd avoid anything that sounded nasely, but I'll give that a go, I can't get high notes/scales like I used to be able to. ;)