Most words and phrases have taken to themselves extended and inclusive meanings. A poet, when using them should be aware of the possibilities that such connotations also bring to the poem. A sea, when it is a "sea of troubles," is no longer a body of salt water; in deep blue sea we need to consider, probably by context, whether deep refers to "blue" or "sea." And this is just one level. Is the blue sea also a sea of blues, therefore a sea of troubles? That's another possibility. Then, like a dream, can it convey longing for distant places, a force limiting expansion of the soul, and so on and so on. All these layers of meaning, whether close to the surface or not, have a presence in a poem.
So a poet must be careful not to distort his clarity of expression by using words and phrases that carry meanings contradictory to what he intends. He must know and understand as much of the possibilities his words may create, what nuances lie hidden among the similes, or how his metaphor may be interpreted.Even then, the poet should not be surprised if someone ascribes to his work a totally subjective meaning or interpretation. The wash of language can validate almost any meaning. The surrealists taught us that.