**Hollow/empty words** (n.) or **ring hollow** (v.), **sound empty/hollow** fits the meaning of , as it explicitly dismisses the subject-matter as unrealistic and reflects the hypocrisy connotation of . However, it fails to reflect the connotation of how the subject-matter sounds great at first glance.
In this case, **idealistic** (adj.) can be used instead, to reflect both the superficial positive quality and the unreality of the subject-matter.
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> It's idealistic to put the happiness of other people before your own.
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> Putting the happiness of other people before your own - how idealistic that is.
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> It's idealistic to expect people to value personality over looks
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> Personality over looks - how idealistic that is.