When it comes to sitcoms about a group of young adult friends behaving badly in New York City in the 1990s, there are a few people might think of. There's the incredible "Living Single," which followed six young Black professionals living their best lives in a Brooklyn brownstone. Then there's "Sex and the City," HBO's twist on the format with a whole lot more onscreen sex. But for many, the two big ones that come to mind are going to be the NBC hits "Seinfeld" and "Friends." Both are shows about absolutely awful people who are nonetheless kind of lovable, and it turns out that because of a series of crossovers, they're actually set in the same fictional universe. 

Both "Seinfeld" and "Friends" aired on NBC during the same era, but there wasn't really much competition between the two shows because fans of one tended to also love the other.