Infantry
"Dig a hole in your backyard while it is raining. Sit in the hole while the water climbs up around your ankles. Pour cold mud down your shirt collar. Sit there for forty-eight hours, and so there is no danger of your dozing off, imagine that a guy is sneaking around waiting for a chance to club you on the head or set your house on fire. Get out of the hole, fill a suitcase full of rocks, pick it up, put a shotgun in your other hand, and walk on the muddiest road you can find. Fall flat on your face every few minutes, as you imagine big meteors streaking down to sock you. If you repeat this performance every three days for several months you may begin to understand why an infantryman gets out of breath. But you still won't understand how he feels when things get tough." -Bill Mauldin
http://www.pbs.org/thewar/search_results.p...ntry&page=8