Left image: A car approaching a Y junction, with the left fork empty, and the right fork filled with a line of cars.
Right image: A car trying to enter the right fork of a Y junction by cutting in between a line of cars. This kind of driving is generally not correct.
This image is funny, as a car is approaching a Y junction, with the left fork empty, and the right fork filled with a line of cars. If it needs to go to the right, it should get behind the line of cars. However, in an attempt to probably go faster, the car tries to cut in line, leading to more traffic,  thereby increasing commute time.