As I continue towards completing my Ph.D., there is one truth I've learned about a doctoral program. That truth is that completing a Ph.D. is 90% hard work, and 10% intelligence. When most people hear that somebody has completed his or her Ph.D., their first thought is, "wow, that person must be smart." I want to dispel that myth right now.
Not that almost all Ph.D.'s I've met aren't very smart men and women, but that is not their defining trait. Their defining trait is the ability, willfulness, desire, and dedication to work hard. I'm sure this is also true in other professions and degrees, but it is not uncommon to work 7-day 80-90 hour+ weeks. And that work includes difficult, as well as menial, work, with looming deadlines.
I strongly believe that if the (average?) American got accepted into a Ph.D. program, and put in the requisite time to read and implement everything they could regarding their chosen field for several years running, that person would undoubtedly be able to complete a doctoral program. Intelligence and creativity are tools to help make completing a Ph.D. easier, but they aren't the main tools at one's disposal. Given, one must have some baseline intelligence to understand everything one learns about his or her field, but that baseline intelligence is something almost everybody has.
So when I meet somebody and I found out they have a Ph.D., my first thought isn't, "wow, you must be smart", but rather, "wow, you sure know how to work hard."