Parallaxe

The trajectory of the object is in a certain distance beside the line on which the eyes see the object. This must be considered when aiming.

Parallaxe

The parallax is also important for safety. Do not try to aim similar when shooting. With darts one can do it, to aim with a view over the device. But when going on for a knife throw, then keep distance to your head, mind your eye.

If this gesture might be a reflex for you, then think about it. Before! Test it: do a careful slow movement, as if you go on for a throw, only in your view plain. Consider what happens.