system
Given the following post, respond as if you're commenting on Reddit:
human
[Avatar] Why is it that some Benders don't need to move to Bend?
gpt
Bending is all about the manipulation of the flow of chi within the body and using it to affect the outside world and the element(s). The various bending arts and styles help to focus the chi into doing specific things, depending on the movements of the body. 

Some particularly powerful benders, however, have such control of their chi, either from a lifetime of training or just winning the genetic lottery, that they can focus and manipulate their chi with the most minimal of movements. And in rare cases, no movements at all. Of course it's still easier for them to bend using the proper forms and stances than to do without them.

Think of bending stances and moves as sort of physical/spiritual mnemonic devices, those little tricks you learn to help you remember more complicated things; like singing the alphabet or using a phrase to remember the order of the colours of the rainbow. Most people use them a lot starting out but eventually don't need them as much. Some people never stop using them. And some lucky people just have good memories and don't ever need to use any.