How to Spot a Fake
Real sources of fun are what psychologists call "renewable pleasures": enjoyable no matter how many times you do them. For example, if you're getting just enough food, eating will be fun for you at every meal. But if you're devouring more than your body needs, you'll need more and more exotic treats to make food interesting.
If you have a voracious need for more and more expensive toys, prestigious awards, kinky sex and so on, the root of your craving probably isn't the sparkle of real fun, but an inner void.