The French like to use pigs to find black truffles because pigs have a great sense of smell. When it comes to choosing an industry, women’s sense of smell is just as good. There are two kinds of industries in the world. In the first kind, as long as you work in that industry, the girls all scramble to marry you—this is a sunrise industry. In the second kind, once you get into that industry, you’re destined to stay single—this is a sunset industry.