Sleep is the most important part of your day, something that you look forward to all day long. The exhaustion of work can often take a toll on you and lead you to daydream about sleep. This usually happens when you wake up tired even after sleeping for good 8 hours. Researchers believe that your body relaxed when you sleep and takes care of all the bodily functions that enable your productivity in the morning. This means that you need to be well-rested before you are ready to take on another day's task.