now. referring to the comment below mine, i have to state that i do not think this poem is about you, it is weird how people think "i" in a poem refers to the author himself, this is never the case. as soon as one has written down any kind of fictional material, he no longer has power over what people do with it, he himself has become an interpreter. if you couldn't get the right clues from a book with an unknown author, literature would be quite worthless.
anywho, this is full of irony. for example, saying "i can only speak what is the worst" but saying it in a poem and then actually naming the poem "flowers" and using the words "trees, butterflies and birds" is definitely a contradiction. the protagonist clearly has words for those kind of things otherwise he'd be in denial. which would be a nice twist to this, too, but i don't see anything pointing out that it could be like this. i like the way this is a kind of pun about the fact that this poem is actual just a medium of communication, something that is made up.
this kind of destroys the protagonists other perceptions of himself, or sets them in relation, at least we know that he is not right about one of the three named things he can't do, so one can doubt that he is right about the other two. i guess he'll see some beautiful stuff, too, since one has to, so this as well is questionable, the fact that he sees those things in his mind and knows what they are, makes me doubt it already.
maybe you wrote this, trying to say that he feels so bad, he's not able to see beauty, but seeing that this has been disproven by the protagonist, who knows. i'm not going to go into that, sorry if that's the way you wanted it to.
the structure in this poem is, fitting in well with the doubtfulness about the protagonists perception of himself, not really straight either. there are "attempted" (not saying you were trying to, i guess this is intentional) rhymes, there is no real structure, the arses are all over the place, sometimes right sometimes they're not. so, did this piece of writing try to be something it may be not?
the last two lines are a hint, what does the interpreter want from this poem? it would be wonderful to see this as another act of denial, the protagonist is more focused on what other people think of him, finding excuses, when he clearly lacks self-reflection. but he finds a good excuse, too; how is he supposed to see what's going on, all he knows is all he ever learned and he probably never learned to reflect on himself.
hope you had a good time writing this,
Actually, I think I would have absolutely loved this if the poem was only the first stanza, because in poetry there's lots of talk about nature but then that second line totally takes the reader for a loop, and the fact that you have no words for those things is great. It's reckless, a bit Bukowski.
The rest of the poem is definitely a bit more indulgent and obviously what I gleaned from the first stanza is not the intention of the poem, but anyway, it comes from a place of frustration and anger and that's good to try to get out if possible.