I once worked in the music section of a store in London
One day, a typical yuppie type wandered in and started asking about classical music. Seeing as I was the only staff member who knew anything about it, said yuppie was pointed in my direction.

"Ah hello. I was wondering if you could help me."
"Of course."
"I'm looking for a particular classical music piece."
"OK."
"Except, I don't know what it's called, or who it's by."
"Err."
"It had a cello in it I think."
"Well that rules out the piano sonatas at least. Can you hum or sing it?"
"No."
"Well, here's Elgar's Cello Concerto in E Minor, if you don't like it, you can bring it back." [He didn't]
(theremin put the lotion in the basket on, Sat 12 May 2012, 10:40, 3 replies)

Like it, or bring it back?
I MUST KNOW
( Zoroastermouse thinks therefore he am, Sat 12 May 2012, 18:28, closed)

He didn't return it.
However, during that same period I also liked to play The Flaming Lips' "Yoshimi Battles The Pink Robots" on the in-store stereo. I had loads of people buy it due to hearing one of the nice songs ("Do You Realize" etc), only to return it after hearing some of the more mad-sounding (to their ears) tracks.
(theremin put the lotion in the basket on, Sun 13 May 2012, 12:56, closed)

As a former worker in a CD store with a classical section,
...these sales were the best in terms of getting repeat customers. People would come back specifically for more random recommendations.
(Ladyfingers is in your wardrobe,, Sun 13 May 2012, 5:03, closed)