Our world is so fast-paced today that we hardly ever have time to get a good rest, we want to do so many things in so little time, we want to keep up with all the things that are happening around. 24hrs just seem too small for us to accomplish all that we wish to, and then we end up getting hooked on caffeine for that extra burst of energy to get us through the day (and our health ends up suffering on the long run). It is really important that we sometimes take a step back and rest.
To some, resting might seem like a lazy thing to (I mean, there is so much work to be done, right?), but then we can't function at our optimal capacity or work efficiently once we are stressed out. You might end up doing what you had wanted to do and maybe at the time you wanted it to be done, but the result wouldn't be a good as what you wanted it to be and then you become hard on yourself, blaming yourself for your inefficiency that is because our brain is one of the key things stress affects. If we want to work at our optimal capacity, then it is important we de-stress.
The thing is that once we are stressed out, our mind gets clouded and no matter how hard we try, we won't be able to get clarity on almost everything, your creativity when you are stressed out is almost zero, and the results you produce is definitely not what you have envisioned. So why don't you empty your mind of all the worries and anything that might induce stress and you will feel rejuvenated physically, mentally etc. There is only so much our human body (and brain) can do, overworking it and taking it way beyond limit when stressed out isn't the best way because we will end up breaking down.
Our body speaks to us, pay attention to it when it tells you to rest, listen to it and do the needful. Stress isn't something we can shy away from, we are bound to get stressed sometimes (it is inevitable) but it is essential that we learn to take some rest once that happens so we can rejuvenate and be our best.