Jersey City, N.J., Unhappy customers can mean trouble for retailers. A study by Verde Group and the Baker Retailing Initiative at the Wharton School at the University of Pennsylvania reported that more than 50% of Americans say if a friend or colleague told them about a negative in-store experience, they would avoid the store, too. About 50% of consumers have had a poor shopping experience, and 31% tell an average of four friends, The Star Ledger reported. The survey generated 1,200 responses from U.S. consumers who made purchases worth less than $2,500 during the four weeks leading up to Christmas 2005, with the average purchase price at $163. Typical problems were slow lines, trouble finding products, staff that didn’t know the product or lacked courtesy, and parking difficulties. “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 the store does to entice shoppers, these people will not set foot in their store,” said Paula Courtney, president of Verde Group.