Behavior; is not about just swinging arms.

Life is the reality of contrast and physics that holds things together.

Think/Feel-Act-Process (Think/Feel)-Reaction.

Does not matter if it's something that does not rely on conscious thought (Behavioral Scripting, I.e. doing something over and over again until it just becomes commonplace for example most adults will be able to have or make breakfast while doing other activities such as talking or reading a book/newspaper without too much trouble). Although it's funny to watch people learn a new task when they are still clumsy and non-adept at it (Slower, more concentration, procrastination of starting the activity and more emotional task).

What happens if you start moving arms and legs around in a vain attempt to show that a character is "alive"? Might as well be showing a magic trick while still memorizing the trick out of the book.

Humans are emotional critters at the very best and very worst of times. We tend to act on our feelings or instinct even before it comes known "the why" the process has been triggered and a lot of people go with the feeling even after it becomes apparent that it's not rational.

Overcoming or even realising basic programming from fight/flight or noise/movement can be very hard. You know the feeling at a party when someone makes a loud noise and you are suddenly switching your attention to follow that someone's actions and then realise with some guilt that you have tuned what the other person (that you were talking to) has been saying to you for about a minute? Or that feeling like you really, really want to punch your boss?

We need to identify, empathise and feel real emotions for us to really connect with anything that is seen to be "living" especially if it is seen to be human or humanoid. Anything other and it will be seen as scary, non life like and very much uncanny valley.  

We really do not swing our arms unless in the following situations: We are really trying to get someone's attention, in the last reaction of slowly falling of a cliff in a vain attempt to grab something, we want people to think we are crazy. Or swinging legs unless; doing a really long march, really wanting to show off shoes/happy attitude/direction of the pub or a comic on stage.

Mostly a lot of our action is really rather small in economy (well, I don't want to seem crazy, do you?). We don't tend to exaggerate our actions unless we feel quite strongly or telling stories.

That means that the whole story telling poses are trying to show to the max range of the character through the dialogue/movement phase is all you got (take into account where the character has been raised, body size/shape/weight, male or female not just in the sense of body structure but also gender biases, even what does they do in their spare time to unwind/connect/feel better about themselves).

A lot is said in the way people do things (how many times have you just looked at a person and just have a impression of them as a whole?) Now we are pushing the idea this empty vessel (the character) is a normal person with hopes, dreams and fears.

I know, I did kinda rant but in someways. You guys "know" this already don't believe in moving an empty vessel around the stage (that's being a puppet to another puppet). This vessel is you in someways as well (like all art forms, you cannot express what you do not know yourself) have fun! Don't let the task become the be all and end all, know that if you are just moving it for the sake of moving it than that is not animation.

Happy animating,
Cassie