[arnaudvalette]

I fail to define what is "fun". I fail also to determine the limit of what is an emotion and what isn't. Emotion must have an effect on my brain, and maybe cause some behavior.

Joy and sadness are emotions, they do encourage specific and somehow different behaviors.

It seems like "fun" is local, and "joy" global. Also "fun" seems to be more immediate and have a specific (shorter) lifespan.

Fun seems to be linked to a situation. When the situation ends, fun ends.

You perfectly identify what is fun while the cause of joy can perfectly be unclear or complex.

But does that make "fun" something else, in nature, than joy ?