We've all felt it prick the back of our necks, especially when we seem to be having a lousy day. The worst is when we're mid-sentence in a passionate debate over the merits of baked vs. regular Cheetos, and a dribble hits our lips, causing us to sputter at an invisible assailant. But are those drops of water falling from the city's A.C.'s slowly poisoning us, drip by drip?

Of course not, according to Slate's Explainer. "As a general rule," the water emitting from an A.C. is in fact sanitary because it's just condensed water vapor that doesn't come into contact with any chemicals. Robot rain, if you will.

However, "in rare cases small amounts of water can be left to stagnate inside the air conditioner" if the drainage tube is clogged, breeding gross strains of bacteria, one of which was responsible for a 1976 outbreak of Legionnaires' disease in a hotel. Apparently Legionnaires' disease is named for the American Legion convention that was meeting at the hotel, and is like having a terrible flu. Kind of a bummer considering we always pictured it going something like The English Patient.

So while you probably shouldn't drink the water, there's no need to fear the drip, and you can even use the water falling from your A.C. (as much as 2 gallons on a hot day) on your plants.