You don’t have to read or repeat jokes to smile; just be cordial and light-hearted. Practice Yoga and meditation. Have unshakable faith in the Divine and in the law of Karma. Be in the company of those who live in knowledge and are humourous.
A research done in England found that a baby smiles 400 times a day, an adolescent 17 times and an adult doesn't smile at all! There lies the trick: You should smile more. Everyday, every morning, look at the mirror and give a good smile to yourself. When you smile, all the muscles get relaxed. The nerves in your brain get relaxed and you get the confidence, courage and energy to move on in life.
Just see why our spirit goes down when somebody says something stupid. And why did they say a stupid thing? Because they had some ‘garbage’ they needed to throw out and you were there ready to ‘catch it’. And once you have ‘caught it’, you hold on to it so passionately. Come on! Wake up! Don't let your smile be snatched away by anybody. Keep it alive with humour. One who ca use humour can sail through any conflict in life.
Usually, you give your anger freely and smile rarely as though a smile is costly. It is in ignorance that anger is cheaper and smile is costly. Actually, a smile is free like the sun, air and water and anger costs you a lot. So, let smile be on your face all the time.