Because I'm an idiot, I moved to a town in April that is now a red-hot Covid-19 hotspot. About 6% of the population of this town currently has Covid-19. So Mrs. Sweetums says, "Let's go walk the dog downtown. There's nobody there. I can visit the bakery there (which is open)." We were down there before when it was in fact empty and safe, so it seemed initially like a good idea.
When we show up there, it turns out there's a fucking street fair in progress with hundreds of people, only about half of whom are wearing face masks. God help me, it still looked like it would be okay to walk to the bakery and back quickly and stay socially distanced out in the middle of the street if need be. It wasn't remotely possible in practice.
Lesson learned: if there's a gathering of hundreds with any unmasked people, even if it looks like there's plenty of room on the street, stay in your car!