In his book "Why we sleep", Matthew Walker distills all of the science about the subject that's been gathered in the last few decades into an easy to read distillation of why this misunderstood activity requires a third of out lives.
It turns out that getting proper sleep is the most effective healthy behavior we can do. It affects every single system in our bodies. Not getting enough of it will make you fatter, stupider, uglier, and the list can keep getting longer. And it doesn't take a lot of sleepless nights to damage you. A few days of sleeping less than 7 hours and you'll be as cognitively impaired as a drunk person. And you won't notice it. You'll think everything is normal. But your results will show otherwise.
Sleep is a much more important part of our lives than we usually think. We should be more careful about the quantity and quality we get each night.