Why do we become so susceptible to nostalgia as we grow older? My theory is that it’s not about what happened in the past. That is, it’s not about the things, events, achievements of the past, nor the quality of any of these things. It’s about how we felt. What we are missing is the emotional content. It’s about the raw emotions like fear, happiness, depression, anger, burning passion, passionate love, big disappointments, insatiable curiosity, sheer excitement, sense of mystery, etc.. As we get older, we seek comfort, stability, predictability, controllability, security, and we manage to achieve them; and in that process we stop struggling, learning, changing, and growing. So, we rely on the memories of our past to artificially create the sense of excitement. We are vicariously experiencing the same emotions through our past selves.