By analyzing the commonalities among the wealthy, we can find common threads which lead to financial success.

We’d all like to get rich, but the reality is that it takes patience and hard work to get there. Before you get rich, you will likely need to hold down an ordinary job for some time. If you want to follow in the footsteps of the wealthy, one of the jobs you should get some experience in is sales.

Sociologist and Historian Rainer Zitelmann conducted research into this topic for his book “The Wealth Elite.” One of the takeaways is that many millionaires and billionaires have worked in sales in the past. Among all the factors taken to account in the study, the most self-reported answer as to why these individuals were successful was their previous sales experience, according to Zitelmann.

Among other jobs held by the wealthy, Warren Buffett delivered newspapers. Mark Cuban held a sales job but says his favorite job was teaching disco dancing to sororities. Jeff Bezos even worked at McDonald’s for a while. Even if the wealthiest, savviest business people in the world have had to work their share of crummy jobs.