Introverts still need social interaction, and still enjoy it, it's just like spending a type of energy to do it. The same way doing a lot of physical activity can feel good, but still be exhausting afterwards, it's like that with introverts and really social events like a party. It's fun, but it's tiring.
And now I have a question for you, as an extrovert, how do you handle being alone with only your own thoughts to keep you company? Does that feel exhausting for you?