Those Lost Years of Youth

In life, we miss many things and miss many things. But for the past things, even if we try hard to redeem them and try to change them, they remain indifferent. We always think that memories are good because they can't hurt us. In fact, memories are very bad, because they keep hurting us... If you could go back in time, which period would you most like to go back to? What do you want to save most?