What I find most odd about this is: you seem aware that you're doing it. The end of the fourth stanza ("The true treasure was the journey, or some drivel like that") suggests a wry understanding of these cliches, and IRONIC use of them throughout the piece. However, as this is the only evidence to suggest this, I do think that my point stands, overall.
Like Orwell said, these pre-packaged phrases save people the trouble of having to think of imagery all their own. But that's not what poetry is about, especially YOUR poem, user. Because YOUR poem has to speak to YOU specifically, not just "any person who's in love." Don't you think?
If Sayori was reading your poem right now, wouldn't you want her to feel like it was written for no one else but her? So we've got to help you avoid phrases and lines which will feel applicable to any generic girl.
So when you say chasing an impossible dream "makes you feel free"........free like what? Don't be free like a flying bird, because that's what EVERYONE is free like. You're more unique than that, user, so immediately discard the first two or three images that come to your mind. Ignore the quick, easy, lazy ones.
As an exercise, next time I want you to get WEIRD with your imagery. Words which will make the reader pause, and wonder what the hell you just said. Get abstract if necessary.
But more importantly, get SPECIFIC. Even if the image itself is rather pedestrian, the details will make the difference.
After all, what is freedom, if not the shipping containers flung off the deck of a ship caught in a southward gale? What is "childishness" if it hasn't got lollipop residue stuck in its hair, and holes worn into the soles of its tap-shoes?
Is it really love if you don't look for her umbrella on the coat-rack when you enter the building, the surest sign that she's arrived before you?
Cheers, mate. Give yourself some space to really experiment, and like I said, to get weird. Because "weird" is unique.