clipped from: www.helpguide.org   
Humor and playfulness are shared pleasures that create a sense of intimacy and connection, two of the healthiest qualities a relationship can have

Why is it important that play be a shared experience in relationships? Play is something we can do alone or as a spectator, but in relationships, play is always a shared experience. The simple fact that we are participating in a playful experience with another person makes it all the more enjoyable. We play together in relationships to:

Be spontaneous
Let go of defensiveness
Release inhibitions
Calm and energize ourselves
Allow honest expression of emotions