What is the main function of hair in the human body?

To help the body in homeostasis of body temperature!Also will stand on end when frightened like a cat but due to evolving to have less hair you just get goosepimples! We probably evolved to have less hair due to our ability to produce clothing!Possibly still have head hair as we either didnt produce hats, or it conferred some advantage such as preventing heatstroke(by protecting the back of the neck and forehead)or sexual selection.  more