DocNrock said:
I do it without even thinking about it.
Everybody does. Kinda like the "flying pinky" many new players have. You have to consciously fight it, and unfortunately it takes a long time to overcome.
I wouldn't lengthen the strap or otherwise lower the guitar, though. That'll make it worse because you'll have to reach farther, and you're already fighting your reach. Usually, the sitting position is nearly perfect so you just have to work at keeping your wrist straight. Standing while playing is where many players have problems with reach because the instrument is invariably slung too low. Note that it's ok to turn your wrist so your palm is facing the guitar body more; it's the bending of the wrist that's the problem.
Of course, I'm as guilty as the next guy for doing what works because nothing succeeds like success. I'm just parroting what my first "real" guitar teacher drummed into my head 100 years ago (for a while he even had me wearing a
wrist brace like bowlers use), and a subsequent teacher of similar talent harped on it as well. They were classically trained, and could do magical things with the instrument. But, even they'd admit that it's something you work toward while never really mastering because sometimes you just gotta do what you gotta do. Thing is, if you don't work at breaking yourself of that habit, you can end up with problems later on that will prevent you from playing well, or even at all. Things like carpal tunnel syndrome or "trigger finger" can put you out of business.