French philosophers are generally not part of the curriculum covering the skills needed for investment banking and financial modelling. However, with the time for summer internships in the banking industry drawing near, I often find myself repeating the same Voltaire quote to MBA students: “Common sense is not so common.”

I have seen prospective banking interns lose a full-time offer because they made avoidable mistakes during internships, committing what might otherwise have been obvious oversights.

Sometimes these squandered opportunities stem from an intern’s overconfidence, which is especially dangerous for MBA students who may feel their previous experience and age have adequately prepared them for the rigours of an investment bank. That is why I remind students heading into a summer internship that a lot of their tasks require uncommon focus, attention to detail and deep levels of analysis.