Not getting enough sleep can affect your day horribly. Sleeping is a way for your body to reboot on energy. When you do not get enough sleep then you do not get enough energy. needless to say, not having enough energy for a busy day is not a good thing. Not getting enough sleep causes your concentration and focus to be off. You become easily distracted and may find it hard to stay on task. You may also experience fatigue right from the get go. Every task becomes harder and you feel like you are moving super slow. You may try to mask this feeling by drinking coffee, other caffeine drinks, or eating sugar, but the effects of theses items are temporary and can not replace the value of sleep. Although it is rare, sometimes when you do not get enough sleep you wake up feeling like you have a lot of energy. You go through the morning with no problem at all and handle business as usual. Unfortunately this effect is often temporary. before your work day or school day is over, you have run out of energy and the true effects of not getting enough sleep start to kick in. Fatigue immediately sets and all you want to do is go and get some sleep.