We all love feeling nostalgic , thinking about the good old days when everything seemed better, cheaper, and more innocent. We think back to our childhood and wonder what happened to the world—why can't things just go back to the way they were? Well, I hate to be that guy, but things were never actually better, and nostalgia was once considered a mental illness. The term " nostalgia " was first coined in the 17th century by a Swiss doctor named Johannes Hofer, who noticed that Swiss soldiers st…