Do you have those favorite old songs? Today I opened my old phone only to find those old songs I liked to hear during junior and early months of senior high school. How amazing bumping into some memories when I heard some songs. Like a song reminds me of someone, another song reminds me of a place, and the other one reminds me of a happy memory. Have you ever felt the same too? Well, this is called "Classical Conditioning Learning Process", in...