The difference between seriousness and sincerity is not how involved you are in the activities of your life, but in how tightly you grip. In fact, I would go even further still: Gripping less tightly can unlock better performance and with much less effort, as I’ve written about before. Simple activities, like playing catch, floating in a pool, or... See more

Seriousness precludes sincerity.

For the most part, you’d be better served by being sincere rather than serious.

I encourage you to tune into the experience of seriousness in your day-to-day life. What aspects feel tight, heavy, and constrained? In these areas, see if you can tune into any undercurrents of enjoyment. In the context of games, the way to let go of seriousness is to focus on just having fun. And the same applies in life.

Playfulness makes it easier to adapt the rules of the game to meet everyone’s needs in the situation. You might decide to invent a new rule, change a rule—or play a new game altogether.

This attitude of “we don’t do that sort of thing around here” can be seen another way: as excessive attachment to the supposed rules of the game.