Humanity’s contact with the stars began with Sputnik, her first satellite, which, rather than send back the bloops and bleeps it was programmed to instead started broadcasting spaceship schematics. After an intenser-than-usual space race, mankind reached the stars, and got their @sses handed to them by a race that picked on newly-spacefaring cultures. So all humanity was brought together by the threat from space. Society, fashion, and technology more-or-less froze in the early 60s. Guys still wear suits to work, female patrolmen wear skirts, bigger computers are better, etc. Although, thanks to the war, there is nevertheless a “Rosie-the-riveter”-like mentality, in which any woman can and does do the same work as a man, just, well, in a feminine way.
What they are known for:
Humans are often called the “Musical People.” It surrounds nearly everything they do. Many other species find it fascinating and beautiful how humans surround themselves by art in this way. Though it can get a little annoying on long-distance trips. And human films, with their artificial soundtracks, are treated as frankly bizarre pieces of avant-garde.
Humans also have a strange lack of division between serious “work” and games and diversions. Other species certainly play games, and have senses of humor, etc. But none brings their creative side to normally descriptive endeavors like math or linguistics, resulting in things like Sudoku or entire languages just for “fun” which leads to:
Contributions to galactic society:
Humanity’s biggest contribution (and it is pretty huge) was the development of the first, true universal language: Unilanu. EVERY spacer learns Unilanu, and many planet-bound people learn it as a second language.