I guess they felt, correctly, that they were not just making a weld, not just making an engine or a rocket, but helping to put people on the moon. "Building a cathedral", indeed.
Much more than that though, they would have been highly skilled people with thousands of hours of welding high pressure piping and exotic metals. It doesn't matter how slowly or carefully somebody goes, or how much they revere what they are working on, if they aren't experienced then they will turn out poor work.
