As an act of relief, it is almost certain that I will be thankful for it. I normally write Sunday to Friday, averaging around three to five pages per day, which equates to a thousand to two thousand words per day by my estimates (though the way my word counter works I need to do several double takes to adjust for counting non-word characters). It is a somewhat grueling schedule, and while I could increase it greatly, my writing quality and own well-being would suffer as a result. Some time off also gives me time to read books, experience other stories that I might otherwise ignore or put to one side, and just let my mind take a rest from the entire story writing process.
As to the first two points, I should explain. When I'm working, I can end up isolating myself from a lot of exterior influences so I can focus on my work. While that can be counterproductive if I cut myself off entirely (which I certainly don't do), putting too much external stuff in my head during working hours can be detrimental to the flow and originality of my work. Example; one of my earliest completed longform works is highly derivative because I used a lot of external stuff as inspiration without due care and attention. If it's an audio or video thing, then it can cause me to stop and focus on that rather than work. Unless it's music, in which case I can work with that and it often helps me construct my mental landscapes and characters. As to the last, I work on my stories constantly in my head - including several stories at once - so taking a rest allows my brain to kick into a low gear and relax, which can give rise to some interesting new ideas when I return to work.
Now to why a rest can be a terrifying prospect. Mainly it leaves me open to the dangers of boredom. I suffer periodically from boredom. I can normally fend this off by walking absolutely miles or going for a cycle ride or doing stuff around the house, but when I just want to relax, I can be difficult to find things. I'm not an avid gamer as I find many games have an unpalatable time sink effect on me, while other pursuits can seem somewhat dull or repetitive. When you can look at the spin of a DVD and remember the entire plot even if you haven't watched it recently, it can get a little difficult finding new things. At the same time, you don't want to be tied to your computer again as you've been essentially tied there for however long it was since your last rest.
But there is also the danger that I might begin losing my edge. I was afraid for the longest time that if I once stopped writing I would lose the spark and skill I had been nurturing since my late teens. Silly, I know. A true writer never forgets, they only need to find the write story or subject, and the words will fly from the typewriter at mach speed. I also need to be aware of the strain to my fingers. Being susceptible to RSI (repetitive strain injury) means that fingers flying across the keyboard can result in the finger joints aching or even hurting if I really push myself. Because of that, I need to watch myself. I've even given myself sore fingertips from a really long session of keyboard crunching to finish a chapter when I set myself a deadline.
Breaks are wonderful and terrible. They give your mind the chance to relax after too long contemplating fictional scenarios, while they also leave you vulnerable to the various negative influences of the world around you and make you realise just how much writing is a part of your life. Either way, breaks are a necessary part of a writer's life. Without breaks, you will burn out, or turn to means of staying active that are more than repulsive to anyone wanting to live a full and healthy life.
To those who are on break, and those who are writing, I have this to say; keep writing, and keep taking the breaks you need. And above all, enjoy what you do.