It's rude to ride slowly in the fast lane.
Harold is a slow driver driving on a two-lane highway, and his route has him making a left turn in a few miles.
Harold wants to make a left-hand turn.
Harold stays in the right-most lane until relatively close to the time he needs to turn.
Harold goes over to the passing lane and stays there, driving slowly, for several miles.
Traffic runs smoothly, and Harold makes his trip without incident.
The other drivers honk at him and tailgate him, and a traffic jam starts.