the individuals are committed to and recognize the need to have fun in the relationship
Humor, fun, playful enjoyment are the oil that allows the gears to run smoothly. Life is work, self growth is work, relationships are work. Fun is what motivates and "smooths" the ride. It's what makes the work enjoyable and not drudgery.
Fun is play and play is what triggers the motivation to continue (practice) which triggers TRUE learning and that is what allows us to master things which allows us to receive recognition, which allows us to make MORE connections, which allows us to have fun and play and.... (as noted in Delivered from Distraction).
Also-this fun and play is what triggers our creativity and our creativity is what allows us to tap into that "other side" of our mind and knowledge where the "answers" come at us easily and seemingly with no effort (as noted in "Living Happily Ever After).