stapler.

Good morning, Sunshine!
(I couldn't resist. Sorry.)

I really like all the images you've got going here. They're really lovely, and it leaves a mysterious feeling in the mind.
I think, though, that what you're trying to say is too much of a mystery.
It isn't easy to see what you're saying at all. The highlighter bit really throws me off. Why are we suddenly talking about highlighters? I think it would be better to end it with you losing the eye and the beak of the duck you tore apart. Now, I'd like to know what that duck represents. Just give us a clue. Because I really doubt that this is actually about your stuffed duck. It's about losing a part of something important, but I don't know what. Don't be completely in this realm of dried flowers, lopsided puzzles, and stapled ducks. Give us a reason why you're in this realm.

Now for some specifics.

grind teeth
at false premises;

You should keep in pronouns. Also, I think you meant "promises."

attach piece that

I think you meant "pieces"

others shop stores
for bric-a-brac,

Omit stores. I keep wanting to emphasize it in my head. But really, shop should be emphasized, and you don't shop at all, meaning that stores is completely unneeded.

and cheap stuffed animals,

I think that cheap is unnecessary here. It emphasizes the fact that, while you didn't buy them, someone else did. And if you say that "others" shop for bric-a-brac, you need to not shop (or be shopped for).

they give my legs rashes.

I don't really like the wording of this line. Try to use an active verb to illustrate, rather than them giving your legs a rash. If "rash" could be used as a verb, I'd say to say "they rash my legs." You could do that, experiment with your words, but I won't force you to.

when insanity dies,

I'd like a previous introduction of insanity if you're going to mention it so late in the poem. In poems, it's not really assumed that the speaker is insane even if they're doing insane things because it's generally figurative.

Altogether, I really liked your imagery. Make sure that you let us know what is actually going on. You can't hide behind stuffed ducks forever. I hope that this review was helpful. Happy poeting!

Hey sunshine, this is an interesting poem. My thoughts:

grind teeth
at false premises;
attach piece that
don't go together
because i like the look
of a lopsided puzzle.

It's a little off here, mostly because I think you omit the pronouns, which is a mistake. I like the first image of grinding teeth, which is like a stapler. And the lopsided puzzle idea is fun and amusing.

others shop stores
for bric-a-brac,
but i pick apart dried flowers
and cheap stuffed animals,
sitting cross-legged
in fluffy white debris,
dry stems piled so high
they give my legs rashes.

Again, your imagery is wonderful here and I am just imagining this girl on her own doing her own thing in her home. But I am starting to wonder if we have any sort of theme developing or if this narrator is just sort of innocently doing her thing.

when insanity dies,
i try to staple back my favorite duck
only to realize one of his eyes is missing
and i lost his beak looking for it.

I am unsure what insanity is dying, since you have not alluded to it before except for maybe the "false premises" in the first paragraph. But these two things are really vague and weak and not as wonderful as what you have been doing with the rest of your poem.

The stapling of the duck is really intriguing. I am imagining the narrator trying to fix a stuffed animal, and it is somewhat humorous and endearing. I liked it.

i count highlighters like blessings-
pink, purple, yellow, pink, orange, yellow-
until i, too, run out of color.

What in the world is going on now? Just...cut this really. Nope nope nope. Now you may have just been going through some exercise about whatever is on your desk at the moment, but before this I wasn't brought so suddenly and dully into that world. Now I'm just wondering why in the world we are speaking of highlighters.

And that last line is so melodramatic and silly. You would do well, quite well!, to simply end it the stanza before. It has this sort of mysterious and odd quality that it leaves your reader pondering a bit before moving on. And that is precisely what you want your reader to do when they are done reading your poetry.