It's past 6:30am here right now, I haven't slept the whole night and I'm currently writing an SoP for college applications. The opening line is,
"Do you ever look at someone and wonder, what is going on in their head?"
Yes, I'm quoting Disney Pixar, something that's also a meme, in the SoP of my college application where my major is Industrial psychology. FML.
Moral: Sleep is important.
Fun fact: Lack of sleep also affects the frontal cortex of your brain which is responsible for decision making. It's the same area in our brain that is targeted when you get high or stoned or whatever you call it.