My friend Kristin sent me a nice article from 1943, written for male supervisors of women in the work force during World War II.
Helpful Hint #8:
"Give every girl adequate rest periods during the day. You have to make allowances for feminine pshychology. A girl has more confidence and is more efficient if she can keep her hair tidied, apply fresh lipstick and wash her hands several times a day."
Sound advice. Nothing wrong with incorporating a little glamor and practicing good hygiene during the work day. Perhaps if men brushed their hair and washed their mouths out with soap several times a day, they'd have more confidence and be more efficient, too.