Here’s my Q&A column from the WSJ this week — and if you have any questions for me, you can tweet them to @danariely with the hashtag #askariely, post a comment on my Ask Ariely Facebook page, or email them to AskAriely@wsj.com.

______________________________________________________

Dear Dan,

This holiday season had me wondering: Why do people prefer to give and receive gift cards rather than cash, which you can use anywhere for anything?

—Van

Gift cards limit the way we can use money, which means that, from a strictly rational viewpoint, they are inferior to cash. But people prefer gift cards because of an irrational emotion called guilt—or, more accurately, because of our need to alleviate guilt.

When we look around us, we feel guilt over our desire for many different things: fancy chocolates, pens, expensive headsets, electronic gadgets, etc. We want these things, but the guilt caused by our wants is powerful, so it sometimes stops us.

When we get money, we’re likely to feel guilty about spending it on our more self-indulgent desires. But when we get a gift card, the guilt is much reduced and sometimes eliminated.

Interestingly, the particular level of guilt alleviation depends on the type of gift card. For example, if the card is an American Express gift card, it is basically the same thing as money, and it doesn’t ease much guilt. But if the gift card is restricted to Tiffany’s or REI, that money suddenly becomes more valuable. A dollar without guilt is worth more than a regular dollar.

And if you got any gift cards this holiday season, of any type, I suggest using them as if they were meant to be spent only in your favorite store—and enjoy them guilt-free.

______________________________________________________

Dear Dan,

I realize that mixing friendship and business isn’t always the best idea, but I’m starting a business with a friend anyway, and I want to know the best way to mix the monetary bits of the business with the social aspects. Is there a single recipe for this?

—Clara

Going into business with people we know and love is indeed tempting. So long as the venture is going well, working with friends and family can be great: The extra trust and commitment that everyone shares can help both the business side and the social relationship.

The problem is that things frequently go awry. Then the damage done is often not just the professional downside plus the social downside; it can be the professional downside multiplied by the social downside.

So I would prepare yourselves by outsourcing any disagreements. Decide upfront that every time you disagree, even on something small, you will both go to somebody external who isn’t personally involved. Each of you will then describe your side of the argument in five minutes or less and let that person decide for you—and no matter what, you will take their advice and never mention the topic again. This way, you not only have a mechanism for resolving disagreements, but you can do so quickly, before any tension can build up and destroy either your friendship or business.

One more thing: Pick a third party whom you both dislike. Some intriguing research shows that when an arbitrator is nasty, both parties feel more camaraderie, work better together to resolve the issue and, of course, want to end the disagreement as soon as possible.

______________________________________________________

Dear Dan,

A while back, a friend did me a favor with the understanding that I would “return the favor” later. At first, I was eager to reciprocate, but after several months, I’ve become less aggressive about offering to find a way to help her out. Do favors have a shelf life?

—Jen

Only in the minds of the people who owe them.

See the original article in the Wall Street Journal here.