Though he has been keeping himself busy since walking away from F1, what with winning Le Mans for a second time and competing in the Dakar Rally and (ahem) the Indy 500, Fernando Alonso must have been kicking himself last year as he watched the progress being made by his old team, McLaren.
His frustration will have been compounded as he watched Max Verstappen secure three wins with a Honda-powered Red Bull, while the Japanese manufacturer's near miss in terms of filling all three podium places in Brazil must have sent the fiery Spaniard apoplectic.
Even as he admitted he was leaving F1, Alonso said that he might return, providing the 2021 regulations mean decent racing and he can find a berth with a competitive team.
Though he recently ended ties with McLaren, the Spaniard, fresh from his drive to 13th in the Dakar Rally, insists that he has not given up on F1, far from it.
"I'm not done with F1," he tells F1 Racing magazine. "2021 is a good opportunity and I feel fresh and ready now. It's something I will explore.
"Formula One is unfinished business because people think that we deserved more than we achieved," he continues, "especially in the last few years... In my museum there are cabinets with a lot of trophies, but nothing recently and that seems a bit weird."
Other than his political machinations, the Spaniard is infamous for leaving teams at almost precisely the moment its fortunes begin to improve, as was the case at Ferrari and more recently McLaren. And with an eye on the rules overhaul intended to shake-up the order and level the playing field, this makes his possible destination all the more intriguing.
"The only problem with new rules is some teams could interpret them differently to others," he says. "You can join a team that is winning now, but if they make a mistake with the regs will people say I made a bad decision again?"
Though by 2021 he will have been out of F1 for two seasons - Kimi Raikkonen was also out of the sport for two years - Alonso believes that his experience in other disciplines has helped improve him as a driver.
"When you do events like Dakar you meet different people with different philosophies I will be ready to come back stronger and, if in the right package, I will win," he says.
"I have so much self-confidence that I know I can take any car and if everything goes well, I should win. Driving is the only thing in life that I know I do well at."
However, his 'difficult' nature means he has burned a number of bridges over the years, and despite his undisputed talent there are teams that would never employ him, which, unless the 2021 regulation really does overhaul the pecking order, makes it hard to see where he might fit in.