Why?

In four short years, from 1914 to 1918, over 10 million men and women serving in armed forces on fronts around the world were killed, while double that number were wounded, disabled and disfigured; and at least another 7 million civilians lost their lives as well. Most died horrific deaths. But as time passes by we tend to forget, a century later, how many sacrifices were made day after day on both sides of one the most deadly conflicts in human history. Civilized Productions has produced a wonderful choral album, Sacrifice and Solace, which features an octet called the Toronto Valour Ensemble who sang these carefully selected and uniquely composed songs from that era. It is available on CD Baby. The simple translation of the Arabic word "jihad" is struggle.

The Struggle for Dignity

During the Great War, once assigned to the front, a combat unit arriving would inevitably need to wind themselves through a maze of trenches; each replete with various forms of life. Upon their approach, typically at dusk, they would see and hear exploding bombs, shells and mortar rounds, as well as machine gun bursts and sniper fire. However, they would likely smell the frontline first. Adding to the dried sweat of all soldiers' uniforms, bandages and encrusted feet, would be the carcasses of not only animals and fallen comrades, but wood, sandbags and tents.
There was the smell of cordite too, not to mention lingering poison gas. In No Man's Land, during the day crows would peck out the eyes of the dead and bodies would swell and turn blue before the putrid gases would eventually escape. It was a haunting smell no soldier could ever forget, and who would have to fight atop the dead, some buried by bomb blasts; the living would then be commanded to dig new trenches among the carnage and, if sadly unlucky enough to fall upon them, to have rotting flesh - the consistency of Camembert cheese - stuck for weeks between their fingernails.
Lice and nits infested soldiers' hair from head to toe, and caused incessant itching. Fearless rats, brown and black, some as big as cats, feasted on soft tissue, carrying with them an array of unpleasantness, each pair easily reproducing hundreds more in a given year - thus there were millions joining the men in the crowded trenches, crawling over faces at night. Adding to the terror of being shot or maimed, disease was rampant, from common ailments suffered by the cold and damp conditions to fungal infections and Trench Fever, caused by lice, which was extremely painful and lasted several months.
Trench Foot affected many combatants along the Western Front, mainly as a result of constantly walking through the soggy, muddy and simply unsanitary conditions, which if untreated would turn gangrenous, to be then followed by amputation in severe cases. There were flies and insects to deal with, and there was excrement, as well as vomit, lining the deadly trenches. Despite rotations, living in a trench was appalling and, being shelled and trapped, sometimes soldiers at the front would not eat for days, even while injured, having had a leg or arm blown off, a piece of metal, shrapnel, a bullet or several embedded in either bone or muscle. 
Throughout the war soldiers spent from days to weeks on end in wet, cold, muddy trenches which alone created many symptoms such as swollen limbs, damaged sensory nerves and inflammation. But, apparently, not one British soldier starved while serving at the front. 
Field kitchens were close to the frontlines, but not close enough so that the enlisted men could ever enjoy a warm meal; besides, eating in filth was repulsive. Stale food, which took over a week to reach them, sent many an able-bodied man to the infirmary with a multitude of stomach and intestinal ailments. The bulk of the British soldier's diet in the trenches was bully beef (tinned corned beef), bread and biscuits. By the winter of 1916 flour was in such short supply that bread was being made with dried ground turnips, and pea soup was flavoured with lumps of horsemeat. 
In this environment, for four years, men did their duty; they killed and were killed, suffered and caused suffering. They also cleaned their rifles, refilled sandbags and drained trenches, chores constantly inspected by officers. They went "over the top" when ordered, and crossed No Man's Land to sit quietly adjacent to the enemy in their Listening Posts with bayonets fixed, or to repair barbed wire. Day and night soldiers were also assigned sentry work, though only for a few hours, as the penalty for falling asleep on the job was death by firing squad. 
This is what greeted a soldier arriving at the front and if he survived all this, whether a bomb or bullet, sickness or disease, rat or insect, among this malignant stagnation and cacophony of most-foul odours, he then might be assigned the task of cleaning their overflowing latrines. 
Augmenting a horrible lack of hygiene, sleep deprivation and faced with the prospect of dying, quickly or slowly, many soldiers also fought the psychological damage inflicted upon them daily - the shock of seeing bodies blown apart, limbs disappear into the mud forever, or having to look into another man's eyes before plunging a bayonet into his stomach, or throwing a grenade into an enemy trench to hear the resulting screams for help go unanswered and drift away. 
During the war, the executions of 306 British and Commonwealth soldiers took place, for crimes such as desertion and cowardice, which still remain controversial, with some believing that many of those executed should have been pardoned as they were suffering from what is now called shell shock. However, then, military commanders would not accept a soldier's failure to return to the front as anything other than desertion, and court martials speedily convicted offenders.  
Private Abe Bevistein, aged sixteen, was shot by firing squad at Labourse, near Calais. As with so many others cases, he had been found guilty of deserting his post. Just before his court martial, Bevistein wrote home to his mother: "We were in the trenches. I was so cold I went out (and took shelter in a farm house). They took me to prison so I will have to go in front of the court. I will try my best to get out of it, so don't worry."
It is estimated that 9 of 10 British soldiers who served in the trenches along the Western Front during World War I actually lived to tell the tale.
Lest we forget.