I'd say the first thing I notice about a woman is her hair.   Maybe it's a guy thing, but I love longer hair, especially when it's worn down.  But a survey I ran across says that 73% of people says that how a person wears and grooms their hair says a lot about their professionalism.

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Also in this survey, it said the color RED is the least professional color of hair in the workplace (Sorry---Linae!!)  And the survey added that women who wear their hair down in the workplace are perceived as less professional than women who wear their hair up.  Again--me I LOVE women when their hair is down!