Keeping our Uber rating pristine is high on our list of priorities . Apparently the same goes for celebrities; they've got to worry about their scores just like the rest of us, as Ashton Kutcher recently revealed.In an appearance on Jimmy Kimmel Live Monday night, Kutcher discussed his Uber rating with the late-night host. Kimmel and Kutcher then pulled up their respective ratings on their phones. Kimmel's was 4.8 stars, and Kutcher's was a hair lower, at 4.79 stars.So what's to blame for Kutcher's less-than-five-star score? "They're calling it 'The Incident,'" Kutcher told Kimmel, speculating about a particular evening that may have lowered his rating. The actor explained that one night, he was drinking vodka with Mila Kunis' father. Kutcher didn't provide more details about the evening, but he did note that he "didn't remember getting in the car." So maybe he wasn't quite that driver's favorite customer ever.As for Kimmel's imperfect rating, he posits that it was because he accidentally took a fellow rider's Uber — and took it all the way to the other person's destination before realizing the mistake. Kutcher and Kimmel also discussed whether or not riders should tip Uber drivers, and Kutcher noted that while outstanding drivers should be recognized for their service, Uber's founder, Travis Kalanick, designed the company to pay drivers enough money that they wouldn't need to rely on tips You can check out the clip below.