In the 17th century they did not have synrthetic gel, they used lard in their hair to style and give it some body, and fighting off vermine was a problem then. And with the high styles, often the hair would be caught on fire by the candels that were every where for lighting purposes. Hair is just significant in so many ways and we see it immediately.
It is no different for men except bad hair days for men just make them look stupid. It is that lift, that boost of confidence that some people like Sigorney Weaver want to give to women. The non-profit Dress For Success program offered unemployed women free hair cuts and makeup sessions and photos for their resumes. You can even feel more articulate with your hair done. The fact is that the average human head contains 100,000 hairs so fix that messy hair already!