Anticipation

Greetings!
My first post on the animation principle 'Anticipation', is centred heavily round information from Richard Williams' book 'The Animator's Survival Kit', haven't heard of it? Buy it, it's excelllant! And a great tool to help start up your hand drawing animation techniques.
Quoting Bill Tytla, Williams claims
" 3 things in animation-
1. Anticipation
2. Action
3. Reaction
And these will imply the rest. Learn to do these things well and you can animate well."

Anticipation is the preparation for an action. Especially in every big action
For example:
Chip and Dale's 'Working for nuts'

Here, where the chipmunks are pulling back the tree branch to have it spring forward, anticipation is used here, as this movement is in preparation of the main action; the branch whipping forward.