Donald and Debra Markowitz buy a house from Mordechai and and Monica Kachlon, and include as part of this transaction a $53,000 second mortgage in favor of the sellers. Plus, thereafter, Mordechai does contractor home improvement work for the Markowitz's on the house. And Debra, who's an attorney, provides legal work to Mordechai.
So there's lots of "services" floating around on both sides. Including, to make matters even more messy, some important non-business "services" as well. Namely, Debra starts having an affair with Mordechai. Eventually leading Donald to initiate divorce proceedings against Debra. Oh, yeah. Mordachai's also driving Donald's Jaguar, but Donald's still making the payments.
You can figure out what happens. Except it's even messier than you might imagine. Mordachai sues for alleged nonpayment of various home improvement projects and personal loans. Then the Markowitz's sue the Kachlons for allegedly initiating foreclosure proceedings on the house. Then Mordachai sues Debra for alleged legal malpractice and breach of fiduciary duty.
Needless to say, a tangled web. And you've only heard half of it. All of which Justice Willhite has to sort out. Which takes over 70 pages. Yikes.
Read the whole thing if you'd like. But I can shorthand the message for you as well. Keep business business and personal personal. And the more interrelated your interactions, the more of a nightmare it will be in the event that things eventually get ugly.
Which they do here. In spades.