Bernhard Schlink said this quote
“ Does everyone feel this way? When I was young, I was perpetually overconfident or insecure. Either I felt completely useless, unattractive, and worthless, or that I was pretty much a success, and everything I did was bound to succeed. When I was confident, I could overcome the hardest challenges. But all it took was the smallest setback for me to be sure that I was utterly worthless. Regaining my self-confidence had nothing to do with success...whether I experienced it as a failure or triumph was utterly dependent on my mood. ”