NEW YORK (CNN/Money) - You love them. You hate them. You can't live without them.

Yes, it's your family. And family joys can be abundant: Thanksgiving dinners, family vacations and a shoulder to cry on.

But try to talk money with parents, siblings and cousins, and you may wonder if home really is where the heart is.

How come your out-for-himself older brother gets to dole out everyone's inheritance from Mom and Dad? Why won't your sister repay the loan you gave her for school? And if you and your family members are in business together -- well, no wonder Tony Soprano prizes his sessions with Dr. Melfi.

"Money brings out the best and the worst in families," said Doug Flynn, a certified financial planner at Flynn/Zito Financial Planning in Garden City, NY. "I've seen people nearly fight to the death over an ashtray. And the nicest people often end up getting the short end of the stick."

Take loans, for example. If one of your kin comes crying for a little help with a down payment, new restaurant or grad school bills, it's heartbreaking to turn them down.

But that doesn't mean you should write just anyone a check. First, decide whether you're comfortable loaning the amount of money requested. Then consider the borrower: Is it your responsible sister who you know will pay back every dime, or your hapless uncle who just wants to guilt you out of some cash?

"Use your good judgment," Flynn said. "Have they hit up everyone else in the family? And if they're underwater with a mortgage, a car loan, their kids' tuition and 10 other bills every month, and you, cousin Anne, don't even have a bill, guess when you're getting paid? Never."

Not surprisingly, the default rate on interpersonal loans is 14 times higher than the 1 to 2 percent rate on bank loans, according to CircleLending.com.

The best way to ensure you get repaid is to set terms and conditions on the loan from the get-go, Flynn said. If the loan has already been made and you're worried you may never see your money again, sit down and create a repayment arrangement. Together, decide on an interest rate. Go online and find an amortization table, and decide on a payment plan, Flynn said.

Or, you can take the process a step further and formalize the loan legally through CircleLending.com, a third-party facilitator that structures interpersonal loans. The company charges a one-time $49 setup fee and a 3 percent service fee.

Seventy-five percent of its customers are siblings, and many are simply fed up with the lack of progress on their loans. It provides legally binding documentation, a repayment schedule, an e-billing service and even direct deposit, said Jill Miller, vice president of marketing for CircleLending.

"Many people come to us with an outstanding situation they've tried to work out," Miller said. "We'll negotiate with the lender and borrower to get mutually agreeable repayment terms. Mixing money and love is tough, and people want a solution."

Among the most common family money disputes are inheritance quarrels, which are particularly painful because they erupt during periods of grief and loss.

"It seems to me that these squabbles come about not because Johnny and Susie want the same trinket, but because of emotional issues that were present before the parents died," said Steve Hartnett, associate director of education for the American Academy of Estate Planning Attorneys.

Emotional tension, jealousy and sibling rivalry, all likely sparks for an inheritance dispute, exist in most families. That's why estate planning lawyers stress the importance of writing a clear, legally binding will, to ease the situation for descendants.

But what seems clear to you may not seem so clear to others, Hartnett said.

"Say you decide to leave your assets to your 'descendants'. But if you had three kids, each with two kids of their own, and one of your children died before you, who gets what? Does everyone get an equal piece? It's not readily apparent," Hartnett added.

(In the above situation, had you decided to leave your assets to your descendants per stirpes, one share would have gone to each of your children, and one divided between the offspring of your deceased child.)

If you are faced with the task of splitting an inheritance left in unclear terms, you'll have to consider everyone's priorities -- no small task.

"Do people just want to [take the most they can], or are they interested in having civilized relations with one another?" said Steven P. Cohen, president of the Negotiation Skills Company.

Be prepared for turbulence. One option is to seek mediation, where a third-party neutral (an attorney or trained mediator) speaks with each individual party and then works to find a mutually agreeable solution, which is then authorized by a court of law.

The advantage to mediation is that parties have some say as to the final arrangement, unlike arbitration or court, where a judge dictates what happens, said Dennis Sandoval, director of education at the American Academy of Estate Planning Attorneys.

If mediation fails, then chances are you'll have to head to court and have a judge determine how assets will be divided.

"You'll have to get some type of declaratory judgment as to what the will or revocable living trust meant to say," said David Cahoone, an estate planning lawyer with the National Association of Estate Planning Attorneys. "And when you start getting into court and getting involved in lawsuits with your family members, it can cost as much as people are willing to spend."

Family-owned businesses present yet another minefield. Problems typically arise from a sense of unequal compensation. In some cases, it's a persistent grumble that an untalented member of the flock gets paid to "do nothing" or that family and non-family members who do the same work don't receive the same pay.

"If you're facing friction from mixing money and family at the office, professionalize your business and establish meritocratic guiding principles that trickle down to affect everyone," said Ira Bryck, director of the UMass Family Business Center.

Objective standards for what constitutes good work, applied across the board, are of paramount importance. That way, you're measuring all employees with the same yardstick: family members, non-family members, overachievers and slackers alike.