Does your employer asks you to stay connected to your work intellectually and emotionally, outside your working hours? For most of us this is not the case, but many people fail to make the transition between the hours spent at work for a living and hours of freedom after work. You read, hours of freedom, those hours are yours, it's your time, you're free to think what you want, do what you want and organise time off as you wish without having to for report results of your actions to a boss or a client: you're on vacation!
No need to search from noon to twelve to understand this principle. Of course, you have other obligations to meet. If you think when you take vacation, you have no obligation to fill, you should perhaps come back on Earth. The only activity you don’t have in vacation, is to work for a living. For everything else, you roughly have the same obligations, but they are made in a different context. Your obligations don’t change much, but the context is quite different. Therefore you must approach your free time with a vision identical to the one of your vacation.