Question: Why do we laugh?

Helen O'Connor answered on 23 Jun 2011:

We all laugh, but there is very little research on how and why we laugh. This is because psychologists usually spend more time researching “problems” people have (like being unhappy) instead of looking at all the things that make us healthy or happy. This has actually led to a new branch of psychology called “positive psychology”.

Whatever the reasons for our laughing, it has been shown that it is good for us in many ways:

It can help reduce the feeling of pain; lowers our blood sugar levels (which helps diabetics and even non-diabetics); can help us be more creative and solve difficult problems; bonds us socially with others; helps our blood vessels function better by increasing blood flow (so its good for our heart and brain function).

So, although exercise is still important for our health, it looks like watching some comedy once or twice a week or having a good laugh with friends might be too!
http://www.psychologytoday.com/articles/200504/laughter-the-best-medicine