Whilst a little hair is nice because it looks sexy, unbuttoning four buttons of your shirt so it's hanging off of your shoulders, revealing not only your chest hair but your back hair too, is going to be unpleasant. Similarly with trousers that are worn too low and you can see hair that you don't want to see over dinner. Please, just keep it covered. Undo one or two buttons (of your shirt, not your trousers) and keep it classy and sexy. Less is more, remember.