I often think that the only truly harmless thing that human beings do together is the making of music. If I include dancing as well, then I've embraced the two videos I offer you today, each of which shows how much pleasure we can get and give in groups, and will, I hope, delight you.
The first relies on surprise and incongruity: you're at a big city train terminal, hustling on in your daily commute when:
The expressions on the faces of the onlookers are something wonderful to see.
The second is surprising because it makes use of technology to "congregate" 182 singers into a truly harmonious choir, singers who have never met each other or, indeed, the conductor/composer:
If you'd like an explanation of how this was accomplished, take a look at this video as well.