Good old days – commonly stylized as "good ol' days" – is a cliché in popular culture used to reference a time considered by the speaker to be better than the current era. It is a form of nostalgia that can reflect homesickness or yearning for long-gone moments.
There is a predisposition, caused by cognitive biases such as rosy retrospection, a form of survivorship bias, for people to view the past more favourably and future more negatively.
Nostalgia is sentimental longing for the past, typically for a period or place with happy personal associations. The word nostalgia is a neoclassical compound derived from Greek, consisting of νόστος (nóstos), a Homeric word meaning "homecoming", and ἄλγος (álgos), meaning "pain"; the word was coined by a 17th-century medical student to describe the anxieties displayed by Swiss mercenaries fighting away from home. Described as a medical condition—a form of melancholy—in the early modern period, it became an important trope in Romanticism.
Nostalgia is associated with a longing for the past, its personalities, possibilities, and events, especially the "good old days" or a "warm childhood". There is a predisposition, caused by cognitive biases such as rosy retrospection, for people to view the past more positively and the future more negatively. When applied to one's beliefs about a society or institution, this is called declinism, which has been described as "a trick of the mind" and as "an emotional strategy, something comforting to snuggle up to when the present day seems intolerably bleak".