Got this information from MarketingPilgrim  which referecnes a Press Release and it suggests that when we hear negative things about a person, place, thing, our imagination adds to it and we’re more likely than not to avoid that thing.

"This study is unlike anything we’ve seen before because it shows that
for every 100 American shoppers, 64 people will be told about a store’s poor
products or services and no matter what that store does to entice shoppers -
sales, promotions, advertising, marketing - those people will not set foot in
their store,"

"If businesses want to stop the bleeding from negative word of mouth,
it’s clear that they need to invest in ensuring that each customer experience
is first rate - from adequate parking, to trained front line staff, to the
right product mix, both in stock and on the shelves,"

    "U.S. businesses should take note - every instance of customer
dissatisfaction has the potential to negatively impact loyalty and ultimately,
the bottom line. With this latest study, we now know that negative word of
mouth is so powerful that it can deter potential customers from ever shopping
at that store," says Ms. Courtney. "But there is hope - by taking steps to
better understand the problems their customers experience, retailers can begin
to immunize themselves against negative word of mouth."

Powerful stuff to think about.