Unrealistic optimism dominates American thinking, Barbara Ehrenreich, author of Nickel and Dimed, told students Tuesday night at the International House. Americans, she said, inappropriately try to find the silver lining of even the most upsetting situations–from breast cancer to financial crises.

“Here’s to speaking out against positive thinking,” Ehrenreich said as she took the stage.

Ehrenreich, whose new book Bright-Sided: How the Relentless Promotion of Positive Thinking Undermines America examines what she calls “mandatory positive thinking,” questioned the expectation of a constant upbeat attitude.

Ehrenreich said the message she heard from support groups when she was diagnosed with breast cancer was that if you’re not cheery all the time, there’s something wrong with you. She couldn’t accept that attitude, even though she knew negative thinking wasn’t the answer either.

“I have an alternative to negative and positive thinking. It’s called realism,” she said, meaning that it’s cruel and unfair to expect people to be upbeat about going through cancer or economic hardship.

Ehrenreich, who also has a Ph.D. in cellular immunology, said the belief that a positive attitude is essential to recovery is simply untrue. “There’s no clear evidence that a positive attitude boosts your immune system.”

When asked what was wrong with the delusion of positive thinking if it made people feel better, Ehrenreich responded, “Reality may be harsh but delusion is always trouble.”

Ehrenreich turned her gaze to the 2008 financial meltdown, pointing it out as one of the most obvious examples of the danger of excessive optimism. Expecting the market to fix everything, a pillar of the Chicago School of Economics, is the most excessive positive thinking, according to Ehrenreich.