There's Nothing To Accomplish

Maybe you can manage to breathe "perfectly" for a while. Maybe you can do it the entire time you're meditating. Then the focus on the breath will be gone. So would the implied perfection with it.

This perfection is bound by a definition. Sooner or later, the breath would become incompatible with this definition. So it will be natural, but not perfect.

Maybe you can keep updating your definition moment after moment. But that means any achievement in breathing perfectly would be nullified a moment later.

The desire to breathe perfectly creates the need to define what perfect is. Which introduces a perpetual mental treadmill.

And if you muster the mental agility and self deception and all the practice to indeed feel that you "did it"?

What's the reward in that? Is that going to last forever?

Is that achieved perfection going to last forever?

Would breathing itself last forever?

Then, what is there to achieve?

Now, can you watch the breath with this freedom?