This just popped into my head because I happened across a YouTube video of one of the Seduced by Tango audition tapes. The guy was really sloping his neck forward.
Ya know the expression "heavy handed"? "With a heavy heart." "Don't be the heavy." "Heavy D."
We leaders need to watch out for being "heavy headed". The tell tale sign is the dramatically sloping neck - as if the leader is holding a bowling ball by his teeth (with a string or sling or something or other...it's the only heavy imagery I could think of...) and trying to keep his face vertical...not looking at the ground in other words...although that is a whole 'nother problem in and of itself...
I think it also comes from wanting to (or unknowingly) make contact with the follower's head. Ms. Hedgehog recently wrote about a variant of the forward slope - "the sharp incline to the right".
Neck straight (in the X and the Y axes)...head up...chin up...gaze to the horizon...like there is an invisible string supporting your head...
Here's Pablo Veron ::
Here's Adrian Costa ::
I'm focusing on the positive...the best posture, in my view. I'm sure you can find some good examples of heavy headedness on your own. Unfortunately, it's pretty common.