Intelligence also doesn't necessarily translate to actual success. I've been through numerous assessments as a child that confirmed I am comfortably in the "green zone" (if measured by IQ, that is), but I also have pretty severe ADHD so I can only really make use of my brain for short periods of time.

I can get a week's worth of work done in a day, but only once a week, and I spend the rest of the week wondering where I'd be if only I could work like that every day. I was also a decent student in school/uni but never near the top of the class, because I couldn't bring myself to study for anything more than a few days before the exam.