How far should one go, while writing a book?

As far as I know, the common opinion about writing of books is that it is the easiest way to earn a lot of money, sitting comfortably in front of a PC, laptop, white sheet of paper, etc. Writing, you don’t have to lift heavy objects, get dirty with machine oil, get killed by a bullet, or by another awful weapon, or get a mental disease like in professions where the life of many people depends on you, etc… Usually, this is what those who never tried to write a story would say. Sometimes, writing could be as hard as any physical work (like digging of channels, for example), creating of a story could have a great influence on a writer’s mental health, the wrong interpretation of a book could lead to many murders… To write well, one has to experience many unpleasant activities, depending on your story, like stealing of valuable objects, cheating on your wife/husband, learning to wield well any weapon, or feeling the enormous fear of a doomed victim, or the many dreadful events accompanying the creation of religion, etc…
Of course, some writers would say if a writer has a good imagination, he or she wouldn’t need any experience to write excellent stories. Many others would claim without experiencing every feeling, activity, job, mishap, etc of your characters, you wouldn’t create true, real adventures, good dialogues, or even a gripping plot. There are some of them who would even swear that a writer should reach the end, writing a good manuscript. They would claim that sometimes it means even to kill someone, or destroy some buildings, or steal an enormous sum of money… These guys would point out that doing evil, one could do a lot of good in some cases, so killing a murderer for example could prevent many other killings. Besides, such a “cruel” deed could be the base of an incredible description and plot, which could reveal some excellent wisdom too…
However, my humble (for the present ;) writing experience shows no writer should become the bad character in reality. We have a saying in Bulgaria (can’t remember the English interpretation): Every evil leads to something good, but there is also something else no one should forget… As some of my characters say: Using evil, even for our own good purposes, will finally make us a part of evil itself. I would point out too that J. R. Tolkien brilliantly showed this in his The Lord Of The Rings, where the evil in the one ring finally changed irreversibly everyone of its bearers…
Furthermore, no one would pay attention to the wisdom in a book if its writer did the same horrible things, described and anathemized in his/her works? According to my humble opinion, there should be a good balance between how horrible our experience should be and our “realistic” works. All the writers must use their life-time experience (like education, courses attended, many events and knowledge acquired in the every day routine, etc.), but it doesn’t mean they have to create such one for the sake of a “real” plot that they could become the evil characters in their stories?
http://www.strategicpublishinggroup.com/title/TaleOfTheRockPieces.html, http://allanbard.hit.bg, http://allanbard.hpage.com, http://www.facebook.com/pages/Author-Allan-Bard-Ivan-Stoikov-Fan-Page-Strategic-Book-Group/121092637984053,
http://www.youtube.com/watch?v=0yw3a5n00FI, http://www.youtube.com/watch?v=_qUA8Avl7ew, http://www.youtube.com/watch?v=8ijJl-6Be88, http://www.youtube.com/watch?v=4vkixN9Nr2Q, http://www.facebook.com/home.php#!/ivanstoikov.allanbard, http:// www.allanbard.blogspot.com, www.allanbard.wordpress.com