Here in middle Georgia we are pested with gnats. And they can buzz in an ear, eye and nose so quickly, it seems amazing. One thing I have tried and actually works is Avon Skin-So-Soft lotion. It smells nice and those gnats don't seem to like it. So we use that when the gnats get crazy.
We also get horse flies but only certain times of the year. And don't let one land on you because they do bite and it really hurts. I have killed some of them measuring an inch long. That is a huge horse fly. But they are too stupid to fly out of the mini-blind I have on the windows in my shop. So once they fly into those blinds, they end up dead by the next day. But they usually aren't around for long anyway.