In one example, a method includes determining, by one or more processors of a computing system included in a vehicle, whether one or more events have occurred that are likely to increase a stress level of an operator of the vehicle, and determining, by the one or more processors, whether the operator is the only person in the vehicle. In this example, the method includes, responsive to determining that one or more events have occurred that are likely to increase the stress level of the operator of the vehicle and that the operator is the only person in the vehicle, outputting, by the one or more processors and for playback by one or more output devices included in the vehicle, media data likely to reduce the stress level of the operator.