What is "it?" 2

It is created by nature. Its intention is unknown. It moves really fast, but, some how, it moves very slowly also. It never tells you what is beyond its presence. It will crash eventually although it seems endless. Some people like it while some don't. Some says it's like an aspirin; some says it's like fire burning them. Ultimately, all of us are flowing with it. So, WHAT IS "it?"