Nostalgia is a bittersweet feeling of longing for the past, especially for times or places that hold happy memories. When your grandmother looks through old photo albums and sighs about “the good old days,” she's feeling nostalgia. When you smell cookies baking and suddenly remember being five years old in your childhood kitchen, that warm, slightly sad feeling is nostalgia.

Nostalgia isn't purely happy. It's that peculiar mix of joy at remembering something wonderful and sadness that it's gone. You might feel nostalgic for summer camp, your old neighborhood, or even just last year when everything felt simpler.

People often feel nostalgic for their childhood, but you can feel nostalgic about anything from the past that mattered to you. Sometimes nostalgia makes the past seem better than it actually was (you might forget the mosquitoes and remember only the campfires). Companies know this and use nostalgia in advertising, bringing back old cartoon characters or candy brands to make adults feel like kids again.

Nostalgia reminds us that our memories and experiences shape who we are, even as we keep moving forward.