Understanding the structure and electronic structure of various surfaces was one of the important problems of solid state physics in the 1980s. By the time the electronic structure in bulk is almost understood, the electronic structure of the surface seems to be a challenging part of the theoretical computation. The scanning tunneling microscope (STM) has contributed greatly to the understanding of the surface structure. STM was powerful enough with its function and made a great contribution to understand various nanostructures, conduction phenomena, spin phenomena and quantum mechanical phenomena. At the end I hope to present our recent finding in pairing mechanism of superconductivity of one of high temperature superconductors. I will explain what I've been studying for the past 37 years, introduce episodes related to it, and share the physical and personal meaning.