To see the attitude of the men back then I recommend the Peter Jackson WW1 documentary movie, "They Shall Not Grow Old."
Talk about the stiff upper lip, these soldiers are talking about some of the most horrendous of times and horrific conditions, rotting corpses, rats feeding on bodies, stepping on to decomposing bodies, and I shit you not, there's only one account where you can clearly hear the poor man break down. All the rest are very matter of fact, even humorous, talk about battle hardened.