This is a bald-faced hornet (Dolichovespula maculata) who is not actually a hornet but a wasp.  

In my opinion, hornets are extremely handsome and it really wouldn't be fair to post a picture of a hornet nest without a picture of the hornet.  These wasps are “eusocial, " meaning they live in a colony and care for each other. It’s like a hippie commune, except the wasps work harder (actually, they work themselves pretty much to death,) and there is no sex since the queen starts the colony having mated the previous year.  As with hippies, the females do the work. 
Macro photograph of bald faced hornet (Dolichovespula maculata,) a wasp looking a the camera
Bald faced hornet (Dolichovespula maculata,) a wasp.
This one was collecting pollen, but these wasps have chewing mouthparts and have a varied diet that includes carrion and picnic scraps. 
I’ve not been stung by one of these (yet), but each year I come across their nests in my woods.  Luckily, they usually nest fairly high up. 
Like most wasps, they are not aggressive away from their nest — if they are feeding and you put your hand in their path, they will happily stroll across it.  
Insects don’t have a lot of cranial space, so to speak, and can only do what they are programmed to do.  For example, if you walk up to a wasp nest and bang on the side, you will trigger a defensive response, and a pack of them will come flying out and sting you — if you are sensible, you will run, but they are also programmed to chase you for a while.  
Away from the nest or hive, they have nothing to protect (except themselves) and no reason to sting; they basically ignore people unless we put our hands on them or somehow get one entangled in our hair or down a shirt.  
It is against the interests of the species to "waste” a sting on anything other than protecting themselves or future generations.   That's why swatting at wasps is a sure way to upset this apple cart, provoke an unnecessary defense reaction, and get stung.  This photo was taken with a Nikon d750 and a 105mm.  I much prefer my Olympus for this sort of photo.