Right. Since you're of the curious sort, I'd like to point you to this podcast. It's guest in the episode I'm about to link is a sleep scientist, he can tell you all about what sleep, and not sleeping does to you. Fun fact I learned from this gentleman, being awake is literally giving yourself brain damage.
More than once I’ve been awake so long I started hallucinating. Pretty wild. Good ol’ military. Push you until you go insane. If something bad happens they’ll say it was the individual’s fault. He/She should have been able to fulfill responsibilities without any sleep.