The ancient art form of yoga is about creating and maintaining balance. If you try to balance on one leg in tree pose you will notice dozens of muscles tweaking and moving in your leg and foot in an effort to maintain this balance. However, as soon as you are perfectly still you will lose balance, and while we aim for stillness, we must continue adapting and shifting to maintain balance.
This physical analogy can be transposed to your brain making numerous calculations when performing any task. The more you practice, the easier you will find it and the more stillness you will achieve. The tweaking is still there, you have just learned to adapt to this situation better. The task is still objectively as difficult as when you originally started out, but you have attained a level of proficiency in it.
While we can never obtain perfection by way of perfect stillness, the beauty is in the striving. It may look like stillness to the untrained eye, yet we know how much we are moving and how little it takes to knock us off balance, whether we become complacent or overextend ourselves.
Much like a photograph published on social media appears to capture the stillness of a moment, leading us to believe the subject is in a permanent state of happiness, there are many moving parts going on behind the photograph in order to create that still image.
We can never be still, lest we begin to topple over. Keep striving and tweaking and notice when you lose balance it is because you tried to be still.