Question for those, like me, that are new to stop motion animation...what skill are you having the most trouble learning?

For me, it's "the illusion of life". My puppets move, I experiment with timing and spacing, I ease in and ease out, I try to incorporate secondary movement, but my puppets just don't seem to be "alive". When I watch professional stop motion animation there is a quality of movement, an "aliveness", a "magic", that just seems to be missing from my own work. Are any other new animators having problems with this in your own animation? What are you finding most challenging as you develop your skills?

For those of you with more experience, what was it that made the most difference in your work? What really brought your puppets to life?

Thanks for responding,