To paraphrase a popular saying: Hell hath no fury like a consumer scorned.

New research shows consumers feel as deeply hurt over a bad transaction with a company they love as they would if jilted by a lover. They feel betrayed and sometimes want to get revenge.

The study, authored by Allison R. Johnson of the University of Western Ontario; Maggie Matear of the Queens University, in Kingston, Ontario; and Matthew Thomson of the University of Western Ontario, and featured in the Journal of Consumer Research, examines why.

What happens when people turn their backs on the brands they once loved?

First up: revenge.

"Customers who were once enthusiastic about a brand may represent a headache for the associated firm beyond the lost revenue of foregone sales because they sometimes become committed to harming the firm," the study authors wrote.

A quick glance at the complaints on will show angry consumers who were once staunchly loyal to a brand, but now want nothing to do with them. And want everyone to know about it.

Lisa Spieker of North Mankato, MN bought a Maytag Neptune washing machine in 2005 that needed servicing six months later, only to find the problem continues to persist, even today, despite numerous visits from the repairman.

"We have been brand loyal and have owned Maytag appliances of all different types, but this experience has changed our mind," said Speiker. "We will never buy a Maytag washing machine again!"

Brandi McFarland of Roy, UT was double-charged at a local Target store and claims the manager not only refused to credit the second charge, but was rude to her as well. She vows never to go back.

"I will actually go out of my way to make my business and personal purchases anywhere except Target," said McFarland.

Why do these people feel so strongly about brands they once favored? According to the study authors, some people identify so strongly with brands that they become relevant to their identity and self-concept. Thus, when people feel betrayed by brands, they experience shame and insecurity.

"As in human relationships, this loss of identity can manifest itself in negative feelings, and subsequent actions may (by design) be unconstructive, malicious, and expressly aimed at hurting the former relationship partner," the authors write.

What to do?

What's a company to do to prevent such heightened emotions? "Rather than trying simply to win customers back, which may only exacerbate the situation, companies may want to explore responses that promote forgiveness, indifference, or effective disengagement," the authors suggest.

This may explain why so many consumers report the company they're upset with refuses to work with them or ignores them. Like an ex-boyfriend or -girlfriend who won't return your calls.

Sometimes a company may want to help embarrassed customers move on—even if it means directing them to a competitor.

"The sooner the customers are happily involved with a new brand, the faster one might expect damage to their self-concept to be repaired and the faster the motive to harm the offending firm might dissipate," the authors conclude.