1 Peter 1:13
Wherefore gird up the loins of your mind, be sober, and hope to the end for the grace that is to be brought unto you at the revelation of Jesus Christ
Sometimes, our minds are flitting from here to there, no real rhythm or soundness of thought and no preparation for what God wants to do.
We have to be sober about who Christ is and what He's done and is doing. We have to have this Gospel carried in all seriousness. There is a time for laughter, fun and enjoyment, but not to the point where your mind comes unraveled and you become unfit for the preaching/teaching of the Gospel of Jesus Christ and His next coming.