Wasps do more than just ruin picnics. A wasp’s nest in your attic or under the eaves in an outbuilding will place the area more or less out of bounds, especially if you’re allergic to wasp stings.
It is, however, possible to remove a small wasp’s nest yourself. It’s important to do it early in the year, before the wasps become aggressive in defending their young. Also it’s best done in the dark, when they’re least active, but this means you can’t risk using a torch.