The Importance of Playfulness and Celebration

Why do we have this idea that holiness or being pious excludes laughter, play, celebration? I don't know. My experience has been people who seem to have a deep relationship with God in a way that is kind of inspiring or I go, oh yeah. I want to kind of be like that. They're always fun people and laugh, easy to be around. And I think that not taking myself so seriously, not feeling so self important, not being self referenced, everything's about me.