In the sense the OP posts I don't know if I ride to relax or not. But, for absolute certain, I ride for FUN. I flat enjoy going out for a ride where I just hammer as hard as I can for the entire time. I also really enjoy going for a slow ride where I stop often to watch the beavers, the birds and anything else that catches my eye. I really enjoy riding with another person, or persons, over whatever distance we agree on. Maybe even stopping for a grease burger or other fat treat. Sometimes, I ride just to see if I can climb that hill. When I do it brings a sense of satisfaction.
In short, for me anyway, variety is the spice of life. It also brings the best physical and mental fitness that I can use for other life activities.