I never understood the whole white noise thing. The sound of running water all night would drive me nuts.
I wonder if that guest did this at her home as well. I'd shudder to think how high her water bill must be..
I am with you on this one as well. I just want QUIET to sleep. Noises of any sort drive me bonkers

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A few years ago we had this couple from the heart of Manhattan for a week. He was a stock broker, she an artist. I Googled their address and it was three blocks from Wall Street, the epitome of the belly of the urban beast in terms of noise, congestion and population density.
Mornings, 1-3 they'd come out for breakfast and looked like death warmed over. We could just tell they weren't sleeping well. Doing the fluff each day, we saw the multiple sleep aids on the bathroom counter. Those first few mornings we got questions like, "Do people in NM disconnect their car alarms?" or "Do fire trucks, ambulances and taxis respond to calls without their sirens or horns here?"
They were both just amazed at just how ingrained those particular sounds were in their heads.
Day 4, they came out for breakfast and we barely recognized them.
Shoulders dropped, very relaxed appearances, glowing faces, big smiles, etc..
They were that way the rest of time and on the last morning, the wife cried and revealed that those last four nights of sleep were the best she had gotten in 20 years of living in New York including during any other vacations they had taken.