Vintage.es has a set of 1910 photos showing all the employees of a gas and electric utility in upstate New York. Some are office workers, some are laborers, some are skilled technicians.
Correlation: The men who are holding a tool, or posing with a truck, are smiling and proud. The others are expressionless, which was the default for photographs in that era.
MEN NEED TO MAKE THINGS. IF MEN AREN’T ALLOWED TO MAKE THINGS, THEY WILL BREAK THINGS.
Polistra's Mill 