Financial planner Barry Eckstein has heard a lot of extravagant spending stories. But when clients were chatting with him about the holidays a couple of years ago, he could not believe his ears.

The couple had bought a mink coat. Not just any mink coat, mind you - a mink coat for the their precious little Yorkie.

"It was custom-made, white, and cost a couple thousand dollars," said Eckstein, of Wantagh, New York. "My initial reaction was: 'Oh boy'."

Canine couture might not be on everybody's shopping list for holiday gifts. But the Furry Furrier is just one end of a spectrum. For the rest of us, even when we know we should not be spending so freely, we do it anyway. It is as if we turn our brains off in November, and then switch them back on in the New Year.

Indeed, almost four in 10 people say they spend more money than expected for holiday gifts, according to a new shopping survey by credit agency Experian. That makes for a whopping $806 per person this holiday season, up from $758 last year.

To finance the spending flurry, 12 percent of people are planning to open up new credit cards for the holiday season - and 9 percent predict that they will be paying off those charges late.

"The majority don't even have a holiday spending budget in place - and it makes it very hard to plan if you don't have a budget," said Rod Griffin, Experian's director of public education.

The two biggest culprits for this holiday brain freeze, according to personal-finance expert Bruce Sellery, author of "Moolala: Why Smart People Do Dumb Things with Their Money": Tradition and guilt.

"Tradition because people think, 'This is the way it's always been done, and there is no other way to do it,' " said Sellery. "And guilt because people feel they have to buy more and more things that nobody really needs."

Avoid The Madness

Since gift-giving is an exchange, you can help both sides avoid what Experian's Griffin calls "Dark January." Simply come to an agreement beforehand with the various friends and family members in your life about who will exchange gifts and a price threshold, and save everyone a ton of money in the process.

Otherwise you could fall into holiday horror stories like Brooklyn-based author and comedian Sara Benincasa. She was once given membership to an "incredibly posh" gym which cost around $3,000, she estimates.