Why do dolphins surf In boat wakes

[boatboss]

Dolphins love to surf and jump in boat wakes. Why is this are they just having fun and catching a free ride. I think that dolphins are having fun but also using the wake To catch a free ride. If I set up the wake of my boat and drag it behind me I will see the dolphins coming from a 1/4" mile away they are swiming as fast as they can just to Get to the boat anb catch the wake.