Hello there, as always it's nice to see a new piece from yoh. I've really come to enjoy your poetry and I seem to be able to relate to I quite a lot too. The title 'illusion' could be about many things as it's a distortion of senses and although illusions distort our perception they are shares by many people so I am intrigued as to know what the content will have in store, if that even makes sense. Please forgive me its 3.20am here and I've not slept lol

They always asked
who you are,
you never
had an answer.
^
This makes me wonder if you're talking about a person or indeed an illusion... I say a person with the way it's as though you're speaking aloud to this 'illusion' of sorts... Maybe it's a spirit which is why you're saying it's an illusion as in it's possibly in your head, which again is why you're speaking aloud trying to make sense of what you've seen yourself as no one else understands it nor have they seen what you've seen. Possibly, who knows?

This time it seemed different,

like the world’s resolution
suddenly was of the
worst quality.
^
This intrigued me because I found myself asking some questions - what's different? Why is it different this time? Because although you make a statement it's as though you've plucked it from mid air, places it kid sentence and we're meant to guess but it's a fantastic way of getting the readers attention that's for sure as it made me want to find out the answers.

Yes,
the clouds are white
but they’re fading,
^
This makes me excited for summer because although I'm not a big lover of the hest, my body sure as hell needs it as I suffer from vitamin deficiency like many people in the UK lol anyways, I digress.. Tho made me ponder on why the clouds are actually white and if infact they are white at all.... Hmm? And then why are there some days when there are many clouds then others there's none at all.. Is this an illusion? You really have made me wonder.

the sun’s
losing her yellow
shades,
^
I hope not I need the sun. Please =) lol

the big old tree
pixelating,
^
This genuinely made me feel sad because if the trees pixelate then we'd all meet out maker sooner than we'd like, unfortunately.

and
you,

evanescing.
^
The end is a pretty sad one because it's like the loss of a loved one and felt like a kick in the teeth.

A fascinating and thought provoking piece with some amazing imagery.
Take care,
Em x

Exactly like Em said, in the first stanza I'm unsure which thing you're talking about, the illusion or people. But that's what's so enjoyable about poetry: sometimes, you can interpret poems in your own way.
It was intriguing reading the rest of the poem. It's well worded. I really love the sixth stanza, it's beautiful to read, despite the sadness.
Then, as you read the last word, it sort of determines that you were speaking about a person all along and that they were disappearing like an illusion, or were never really there.. You put a solid lump in my throat!
But then, if you were speaking about an illusion since the beginning, the last word would work just as well, as in ' the illusion disappears'.
Anyway, a fantastic piece of poetry.