If consumers don't realize that now, they certainly will when they receive their first paychecks in 2013, said Ellen Zentner, senior U.S. economist for Nomura.

"The expiration of the payroll tax holiday will immediately affect personal income and spending in January, regardless of how it affects consumer confidence," she said. "All workers will see their take-home pay decline on Jan 1 and it's simple math -- that means that's less aggregate income and therefore less aggregate spending to start off the year."