I’ve just found this image puporting to show you the best way to sit. Good grief! This must be a contender for the Darwin awards….
If you can’t see what’s wrong, use your mind’s eye to make imagine this guy standing. Pull his legs round anti-clockwise until the marked angle is 180 deg; now stand him vertically. You’re now looking at one of the worse cases of Forward Head Syndrome you’ll ever see. He would be staring at the floor all day when he’s standing up. Now imagine the effects of sitting on a chair like this for month after month.
This way lies madness!