Okay, this is not my favorite insect. Yellowjackets are aggressive (especially in the fall) hornets. They often nest in the ground, which can be surprising when the lawnmower travels over their entrance hole. They will also build nests in openings in houses. We once had a nest above the ceiling in our bedroom. On the upside, they’re important pollinators and they also prey on garden pests such as caterpillars.