Everything you need to know about fun.
According to Wikipedia, “Happiness, in the context of mental or emotional states, is positive or pleasant emotions ranging from contentment to intense joy. Other forms include life satisfaction, well-being, subjective well-being, flourishing and eudaimonia.”
Fun is defined by the Oxford English Dictionary as "light-hearted pleasure, enjoyment, or amusement; boisterous joviality or merrymaking; entertainment.”
So basically, there is not much difference between happiness and fun. Fun is mostly short-term and at the moment joy, while happiness is mostly long-term and long-lasting feeling. Without doing fun things, there is no way that people can have happiness. Having fun is not always bring happiness at the end. For example, eating dessert after every meal is fun, but most people would be happier if they were 15lbs lighter. There are so many fun things to do, but you have to choose the ones that can truly bring happiness to you.