One Flew Over the Cuckoo’s Nest (1975)
Jack Nicholson, already 20 years into his career, stars as a patient in a mental institution. Nurse Ratched, a sick and twisted caregiver, rules the ward. A young Danny DeVito will impress you. The movie itself will gaslight you. And the treatment of the mentally ill will horrify you, but it’s not the 21st century, so it’s expected.