In our bodies there are two kinds of autonomic nerve systems. They are the sympathetic parasympathetic nerves that control internal organs. Alarming, discomfort and quick-tempers make the sympathetic nerves too sensitive so that the heart is harmed, while laughter stimulates parasympathetic nerves and makes the heart function properly, and it gives our body a sense of easiness. In addition, laughter relaxes the tension and opens the heart so that we can have peaceful fellowship with others. Believers in the almighty God can give thanks in all their ways and rejoice and smile in any circumstances, for God causes all things to work together to the good for them.
"Rejoice always; pray without ceasing; in everything give thanks; for this is God's will for you in Christ Jesus." (1 Thessalonians 5:16-18)