Just looking at the footage of them going over the wall, probably knowing they were going to die. Then you think of the modern war systems that have no any human contact.Total respect for every one of them.
That might have been true in many other battles, but on the first day of the Somme salient it was in fact probably mostly the opposite.
This was the first sizeable introduction of the pals battalions in any significant number and further exacerbated by inexperienced NCOs and officers.
They saw the barrage, which fuelled their confidence, and their inexperience meant they readily believed the propaganda of upcoming success.
Would there have been apprehension? Yes. Fear? Of course in most. But overall, they were heavily confidence of a significant victory.
As
@ToffeeDoug rightly mentions though, the barrage was heavily ineffective. In addition, they held the high ground over the sweeping plains.
Add to that the fact that the mine under Hawthorn Ridge Redoub was blown almost ten minutes early, apparently so it could be easily filmed.
This gave the German's significant notice of the fore coming attack. Walking forwards towards the plateau they literally stood no chance.