see (something) through rose-colored glasses

To assume a generally optimistic and cheerful attitude toward something; to focus only or mostly on the positive aspects of something. Nostalgia can be misleading—we all tend to see our childhoods through rose-colored glasses. I think Mary is only capable of seeing things through rose-colored glasses, like she's in complete denial of the negative things in life!

Also, look through rose-colored glasses. Take an optimistic view of something, as in Kate enjoys just about every activity; she sees the world through rose-colored glasses, or If only Marvin wouldn't be so critical, if he could look through rose-colored glasses once in a while, he'd be much happier . The adjectives rosy and rose-colored have been used in the sense of "hopeful" or "optimistic" since the 1700s; the current idiom dates from the 1850s.

To view events and people very positively, seeing only their good points; unmitigated optimism. This term began to be used figuratively by the 1850s. “I was young . . . and I saw everything through rose-coloured spectacles,” wrote Princess Pauline Metternich (Days That Are No More, 1921). A twentieth-century synonym is to see the glass half full, to see the favorable aspect of circumstances, to look on the bright side. The antonym, to see the glass half empty, is also current. “This . . . group . . . looks at a reservoir that is half full and doomfully declares that it’s half empty” (New York Times, 1981).