YouTube has become one of the online service platforms where people spend the most time, but little research has been done on the reasons why users spend a lot of time on the service. This study expected that the capabilities of the YouTube recommender system will make users watch unplanned videos and stay for a long time. A research model is proposed that the preference fit, which is the ability to help decision making by suggesting recommendation alternatives, has a positive effect on consumers’ flow, and leading to urges to view and impulse viewing. The result shows that the preference fit of the YouTube recommender system has a positive effect on the concentration, sense of control, and enjoyment that makes up online flow, and among them, sense of control and enjoyment are affecting impulse viewing through urges to view. In terms of the service provider, this study presents the need to enhance the capabilities of the recommender system, and from the consumer’s perspective, it implies the need to use a regulating strategy to manage impulse choices that cannot be seen as rational actions.