What gets me the most is that all the "correct typing posture" images seem to indicate that it's best to keep the keyboard low, close to you, elbows bent around 90 degrees. In this position the palms are naturally positioned so thumbs are pointing up, and you need to force the palms to be level with the keyboard (that's pronation/supination if I recall correctly). That's just madness to me, I can't last more than few minutes in that position.