I walked out of my first examination almost certain I had failed. I got my results back, and learned I had passed with honors. This situation repeated itself with depressing regularity over the next few semesters.

Back during my schooldays I was often certain that I had failed a test, just like many other people in my class. It turned out that most of the time the others didn't fail the test while I did. I concluded that they are for some reason just bullshitting about their self-assessments, it didn't occur to me that they just repeatedly failed to accurately predict their own success.