He had to do Math 55 to realize that there were people smarter than he was. Not too many people can readily appreciate what this means. I think you have to have participated in national-level math competitions to be able to understand the quality of person it takes to do this.

It reminds of the line from Good Will Hunting where the Professor says that only a handful of people in the world were smart enough to even tell the difference, even though it was grand, between himself and Will.

If your definition of a 'really-smart person' is someone who can ace the SATs or get into Harvard, then you probably won't be able to tell the difference between such a person and Bill Gates. There is a world of difference between the level of intelligence required to ace the SATs and level required to handle Math 55.