Originally Posted by treyes
Your question is a bit loose-ended.The expressions could be construed from the stand point, of semantics,grammar or style(literary)...
Semantically,the first expression could be interpreted to mean"being an unrealistic optimist...one who only sees the positive side of everything(as if life were an array of melodies)...the second expression may be given this explanation"to have little or no respect,interest or belief in the quality of something.
Grammatically,each of the two expressions "passes" as an example of noun phrase
Literarily,they could be metaphoric or idiomatic...in fact,all idioms are examples of metaphor...
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