One question that I always ask recruits is whether they have ever been around somebody who is dead. If the only answer I get is, "I went to the funeral home once," we are in for a ride. The recruits who are exceptions to this are those who have come from another emergency services background (ambulance or volunteer fire/rescue). Hospital workers and war veterans may also have exposure in this area. But for a fresh recruit that has never seen someone who is—as we say in the South—"bad dead," well, the show will begin soon.
If you believe for one moment that looking at crime scene photos or renting horror flicks will prepare you, there are some other 'things' in store. Photos and videos are one dimensional and short lived. It is the smell that gets you the first time. I have never been able to duplicate the essence of a dead guy for scenario training but it sure would lighten up things! You can shut your eyes and cover your ears, but the smell is what lingers and shocks the system.
You will have to follow your departmental guidelines regarding what you can and cannot do on a putrid case. Some old timers used to smoke cigars feverishly; however smoking on a crime scene or in the public eye is now frowned upon. Cheap after-shave or a menthol rub in the mask or copious amounts around the nose helps. On some of the more aromatic calls it always pays to have a buddy on the fire department who can lend you a respirator.
Things that give you the willies…
I have had some trainees who have certain known phobias. Some were not crazy about heights or were claustrophobic (no wonder they did not take the fire test). A few did not like dogs or what have you. The key here is that they had some conception of what difficulties they might encounter in the future. One lad that I recall had a bugaboo about getting caught in the dark. He carried with him at least three flashlights on dayshift. It is important to compensate for your weaknesses without letting it bog you down.