British Army officers weren’t all “posh” - no less than 1,016 had worked in coal mines before the war.
On average, a British soldier on the western front spent 3 days a month on the front line, 7 in reserve, and the rest away from the fighting recuperating.
Statistically most British soldiers actually gained weight during their time overseas (unlike their French and German counterparts).
Despite the myth that ordinary soldiers were sent to their death by posh cowards, the reverse is actually true - 20% of private school-educated “upper class” soldiers were killed during the war compared to 11% of “ordinary” soldiers.
Roughly the same number of horses died on the Western Front as humans.
9/10 Tommies survived the trenches.
Most people didn’t think it would all be “over by Christmas” - for one, the Secretary of State for War predicted a long slog in 1914.