I came across this interesting story while reading Donald Trump's 'Why we want you to be rich':
Being stubborn is a big part of being a winner. [...] My father used to tell us this story about a guy who loved soda, so he went into the soda business, with a product he called 3UP. It failed. So he started again with a product called 4UP. It failed, too. So he decided to name his product 5UP and worked just as hard to make it work, but sure enough, it failed again. He realized that he still loved soda, so he tried again with a product named 6UP. It failed, and he gave up completely. Then, a few years later, someone else came up with a soda product and named it 7UP, which became a huge success.
I wonder if it is true.