One person in the office gets the flu, and soon everybody in their row has it.
And as paranoid as people think they are about germs these days, with their antibacterial lotions and careful hand-washing after even briefly touching their genitals, the truth is most of us still have no freaking idea where we’re picking up these germs.
But if you carried around a microscope everywhere you went, there are a whole lot of everyday things you’d be a lot more hesitant to rub all over your hands.