The Gemara Bava Metzia 59a (about 12 lines from the bottom of the page)states that most family argument are over money matters:
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Yet, that is not always the case:
I was once in a restaurant and I said that most “Shalom Bayis” issues revolve around money matters, and the proof, “Show me someone who puts down on the table every Friday before light candles $3,500 cash. I will bet you that there are no arguments in that house”. A man next table turned around to me and said, may I interject. I said “sure”. He said. “I used to put down more than $3,500 every week, and it still didn’t help”.