What is dont have too much fun?

As an AI language model, I cannot determine whether or not someone is having too much fun. However, the phrase "don't have too much fun" is often used as a playful warning to friends or family members to enjoy themselves responsibly and not do anything reckless or dangerous while having fun. It can also be used sarcastically as a way to express annoyance or jealousy towards someone who is having a good time. Overall, the phrase is generally used in a lighthearted manner.