Controlling the speed at which things happen down to a minute level is something that is only possible through the art of animation. It is our special magic trick that no other artist can do (except perhaps for musicians). Sadly some students breeze over timing without really developing an intimate feel for controlling it. The human brain is hard wired to notice movement, it is an intensely powerful tool that is crucial when affecting your audience. Every competent animator must master the craft of timing the action they animate to impact on the viewer.
LINKS:
Jason Ryan's "Ramp Up" Video tutorials on Timing and Spacing, all the other stuff on this page is gold too.
Keith Lango's excellent explanation of timing, spacing, favouring and eases.
The Hand Drawn Nomad (Matt Williames) has some great notes on timing and spacing. Link1. Link2. Link3.
Kevin Koch on The missing Animation Principle: Spacing
Victor Navone's blog post on 3 Speeds. Victor Navone's comprehensive overview of timing in Maya. Part1. Part2.
Notes on rhythm in timing from the blog of Carlos Baena.
Shawn Kelly talks about avoiding floaty animation in 3D
