SAN FRANCISCO (CBS SF) – The holiday shopping season doesn’t end when the wrapping paper comes off those Christmas presents; it in fact is just the beginning.

Long lines are expected at shops throughout the Bay Area on Monday as people return those unwanted gifts and take advantage of after-Christmas discounts according to Golden Gate University Professor of Psychology and Marketing Kit Yarrow.

KCBS’ Tim Ryan Reports:

“Most Americans look at the day after Christmas as one of their favorite days to shop,” said Yarrow. “They have gift cards, things they might want to return and everything seems to be on sale. So it’s really a huge, huge shopping day for consumers.”

But Yarrow cautions people about returning gifts the day after Christmas.

“It is a good day to go out there and get clearance merchandise. Some people need to return in order to buy something new, but return lines are going to be long,” she said. “Retailers prepare as best they can for them but it is going to be a tedious process.”

Yarrow issues a final piece of advice for those who might have a gift card to use. Just because you have a gift card doesn’t mean you have to rush off and get something you really don’t need.

(Copyright 2011 by CBS San Francisco. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)