Laughter is important to your relationships. Laughter glues you together so the stress of life and relationship challenges don’t break you. It holds a strong, healthy, and lasting relationship. Going on a friend trip/ weekend where you can kick back and laugh together is a great example. It can be just meeting for drinks/hot beverage or your meal of choice. It’s good to have a good level of laughing together so you can get through conflicts well. 
On a scientific/mental level, exhibiting humor and laughter and joy have protective qualities. It can improve brain function. It helps reduce cortisol (stress hormone) and builds mental resilience. Laughing increases the brain’s endorphin production. (Endorphins are the happy chemicals that reduce stress, boosts mood, and relieves pain.) Laughter also increases your oxygen intake and blood flow and circulation, which can lead to better brain health.
When was the last time you had a good laugh with a friend?