The Vancouver Canucks were outscored by the Boston Bruins 23-8 in the Stanley Cup finals, and yet the Canucks managed to win 3 games and stretch the series to a deciding seventh game. A lesson here is that the margin of victory in each game isn’t important. However, this sports lesson does not carry over to personal finance.
When it comes to your money, the margin of victory (or loss) matters a great deal. A single poor choice when buying a car can cost you more than the total savings in years of carefully finding the cheapest gas prices. It’s dangerous to scrimp on small things and use this as a justification for splurging on something expensive.
Psychology plays a role here. Sometimes when we know that we’re spending money we shouldn’t spend, we think “if I’m going to break the rules, I might as well go all the way.” This way of thinking is just as wrong with finances as it is with diet. Having one cookie or ten cookies may both violate the rules for a particular diet, but small transgressions are clearly better than big ones.
In hockey we only count the number of battles (games) won, but in personal finance, we add up the margins of victory of all the individual battles.