Timing will be quicker or slower depending on the number of frames between given action. Correct timing means objects appear to follow laws of physics. Timing is crucial to establish a character's mood, emotion, and reaction. and how objects should react to force like a push.
Natural action tends happen along an arched trajectory, In animations that follow this principle action will follow along implied "arcs" this creates a more realistic effect. Natural movement such as the movement of a limb should follow an arced trajectory minus mechanical movement, which typically moves across liner lines. An object in motion which doesn’t adhere to a natural arc will appear erratic rather than fluid. when animating you should understand all poses between the two extreme poses, limbs that extend past a logical arc don’t look natural. As momentum increases, arcs flatten out in moving ahead and broaden in turns.
Perceptive Graphic Designer thinking out of the box for discerning clients.