Ear hair. Why why why?
Now, you thirty-something (and beyond) guys, when you consider how much plucking, waxing, electrolysis, dyeing, cold-creaming etc that girls have done to be attractive to you - the least you could do is attend to that little outcrop in your ears.
They may never enter your head but they will shoot out of it, they will be noticed and they will not score you any points. (A little nostril alertness wouldn’t go amiss either...)