My bona fide serious answer is "Where the Hell is Matt?" from 2008.

https://www.youtube.com/watch?v=zlfKdbWwruY

It's a montage of dozens of disparate, diverse locations all around the world, showing us in dozens of situations from poor to rich, young to old, many ethnic groups, both genders...and all of those humans are doing the same thing. They're dancing, and it is giving them joy.

It gives numerous examples of our culture, our clothing, our architecture, diverse biomes, animal and plant life, and it's set to a wondrously beautiful piece of music that encompasses multiple styles of how we express ourselves artistically.

Obviously an alien would have no context, would not recognize the significance of a smile like all humans, even the blind, do, but if we're going to introduce ourselves, we might as well start off on the right foot and see what they think. To me, this video represents the human emotion of joy, and it is one of the few things on Youtube that I earnestly feel are works of art and worth keeping as notable pieces of our civilization.