There is a scene where Smokey is showing McQueen pictures and memories of him and Doc together. We even see some flashback scenes of them having fun together. And bitter music plays in the background. Some viewers might find this scene a bit emotional.
Lightning McQueen has an enraged outburst at Cruz Ramirez, dealing with how stressed and confused he is, and why he needs revenge on the Piston Cup rookie race cars.
McQueen experiences the most darkest, distressing, and devastating crash in the first half of the movie. It's super upsetting for young children and those who grew up with the Cars franchise.