Good question. Unfortunately, no simple answer. Raymond Smullyan wrote this story comparing laughter and humor to a kind of zen experience; you either get it or you don't. So to be fun and exciting, you have to discover fun and excitement. Try new things, things that you wouldn't normally do. Do things spontaneously. Expose yourself to comedy, listen to more jokes, but don't try too hard to "get" it. if it doesn't make you laugh the first time, it probably never will.
Now, how to SEEM fun loving and energetic to people, in a party or other social situation? That's harder. Especially for us. Be energetic without being frenzied. Be the center of conversation without dominating it. Be teasing without being mean. Be complimentary without being a suck up. Always have a joke ready, but don't make everything a joke. Always smile, but don't be goofy. OK, got all that? Now do it all effortlessly, like that's just how you always are.
Yeah, it's a pain being popular.
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Everything would be better if you were in charge.