This wasp just started a nest on our porch. Why is this a good thing? (side note: Note the eggs in the top row of cells. Not part of the answer, but fun to see.)
This is a species of Polistes Wasp, commonly known as Paper Wasps. They are related to hornets and yellowjackets, but they are much less aggressive, usually only stinging when their nest is disturbed, or when you sit down on one. They are predatory, eating a wide variety of insects, and they are particularly good at catching deer flies, mosquitos, and other annoying insects. They also like caterpillars, which makes them a favorite of gardeners. As long as you are not allergic and their nest is not someplace where you will bump into it, consider letting these wasps stick around.