Jenson Button has admitted he stayed in Formula One "one year too long", which caused him to fall out of love with the sport.
The Briton brought a 17-year spell in Formula One to an end last season at the age of 37, but believes his career might have stretched 12 months too far.
"I miss the racing," Button told reporters in Suzuka, ahead of this weekend's Japanese Grand Prix.
"[But] I sort of fell out of love a little bit with motorsport. I think maybe I left it a year too long racing in Formula One.
Button moved to McLaren a year after winning his maiden world title in 2009 but the decision proved to be ill-timed as the Woking-based team struggled to remain competitive. McLaren has not won a race since 2012 and has not finished on the podium since the opening race of the 2014 season, which made things even more difficult for Button.
"The last two years [at McLaren] were tough," explained the former world champion. "Once you have been lucky enough to be in a position to achieve in this sport and had some great years with McLaren, to suddenly have a few years of not being able to achieve and seeing the guys at the front fighting for wins every race [...] It is tough, it really is. I probably left it a bit too long."
Button, who now spends most of his time in the US and has become a keen triathlete, replaced Fernando Alonso at this season's Monaco Grand Prix, as the Spaniard was in the US racing in the prestigious Indianapolis 500.
However, the 37-year-old ruled out following the example of his former teammate to race across the Atlantic in IndyCar.
"There are some great drivers racing in IndyCar, but it scares the sh*t out of me," he said. "I'm amazed they still race. Very brave guys. But I wouldn't touch that. I don't feel it's necessary at this point in my career."
Button returned to racing at the 1,000km Suzuka, an endurance event for Super GT cars, which he "absolutely loved" and vowed to race in a similar event next year.
"As soon as we finished, I wanted to get back in the car and do it all again," he said. "It has been a while since I've had that feeling.
"Next year I will be racing something. I don't know what yet, whether it will be in America, or Europe, or Japan. There are a few options and I want to do a full season and take it properly seriously."