They look at tons of items that are optional and consider them mandatory, such as private schooling. There are some really good public school options in San Francisco, you just have to work like crazy to get your kid in there. I think it's more about projecting a sort of lifestyle.

Another is constant eating out. Everyone likes to now and then, but when it's constant it's mostly just lack of self-control and awareness of one's finances. I've known people who moaned they could not afford a vacation but dropped hundreds every month on meals or (worse) drinks out.

The temptations are everywhere in the city, but there are so many cheap or free options and the city can also be a good place to save if you take advantage of the higher salaries without engaging in lifestyle inflation.