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!
see through rose-colored glasses
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.