When Fernando Alonso leaves Formula 1 at the end of the year he will do so with the peculiar distinction of being a two-time world champion whose potential went unfulfilled.
Winning one title is a major achievement, so how can two be underwhelming? That is the measure of Alonso's unique career.
At the end of 2006, as a newly crowned double world champion, Alonso looked to be poised to have a huge impact on F1's record books. Instead, what happened next severed that timeline and set Alonso on a new course of frustration and missed opportunities.