A lot of it came from Fox being the young upstart network that wanted to make waves. They started green lighting shows that no other network would put on air and it let the writers cut loose and even make fun of Fox as a network. It made them cool and less stuffy, while letting them grab onto the Gen X/Millennial core audience group. Lots of other channels did the same thing and were successful, but rarely to the degree of late 80s - early 90s Fox.