You often hear advice from successful people that you should “Follow your passion.” That sounds about right. Passion will presumably give you high energy, high resistance to rejection and high determination. Passionate people are more persuasive, too. Those are all good things, right?

Here’s the counterargument: When I was a commercial loan officer for a large bank in San Francisco, my boss taught us that you should never make a loan to someone who is following his passion. For example, you don’t want to give money to a sports enthusiast who is starting a sports store to pursue his passion for all things sporty. That guy is a bad bet, passion and all. He’s in business for the wrong reason.

My boss at the time, who had been a commercial lender for over thirty years, said the best loan customer is one who has no passion whatsoever, just a desire to work hard at something that looks good on a spreadsheet. Maybe the loan customer wants to start a dry cleaning store, or invest in a fast food franchise – boring stuff. That’s the person you bet on. You want the grinder, not the guy who loves his job.

So who’s right? Is passion a useful tool for success, or is it just something that makes you irrational?

My hypothesis is that passionate people are more likely to take big risks in the pursuit of unlikely goals, and so you would expect to see more failures and more huge successes among the passionate. Passionate people who fail don’t get a chance to offer their advice to the rest of us. But successful passionate people are writing books and answering interview questions about their secrets for success every day. Naturally those successful people want you to believe that success is a product of their awesomeness, but they also want to retain some humility. One can’t be humble and say, “I succeeded because I am far smarter than the average person.” But you can say your passion was a key to your success, because everyone can be passionate about something or other, right? Passion sounds more accessible. If you’re dumb, there’s not much you can do about it, but passion is something we think anyone can generate in the right circumstances. Passion feels very democratic. It is the people’s talent, available to all.

It’s also mostly bullshit.

Consider two entrepreneurs. Everything else being equal, one is passionate and possesses average talent, while the other is exceedingly brilliant, full of energy, and highly determined to succeed. Which one do you bet on?

It’s easy to be passionate about things that are working out, and that distorts our impression of the importance of passion. I’ve been involved in several dozen business ventures over the course of my life and each one made me excited at the start. You might even call it passion. The ones that didn’t work out – and that would be most of them – slowly drained my passion as they failed. The few that worked became more exciting as they succeeded. As a result, it looks as if the projects I was most passionate about were also the ones that worked. But objectively, the passion evolved at the same rate as the success. Success caused passion more than passion caused success.

Passion can also be a simple marker for talent. We humans tend to enjoy doing things we are good at while not enjoying things we suck at. We’re also fairly good at predicting what we might be good at before we try. I was passionate about tennis the first day I picked up a racket, and I’ve played all my life, but I also knew it was the type of thing I could be good at, unlike basketball or football. So sometimes passion is simply a byproduct of knowing you will be good at something.

I hate selling, but I know it’s because I’m bad at it. If I were a sensational sales person, or had potential to be one, I’d probably feel passionate about sales. And people who observed my success would assume my passion was causing my success as opposed to being a mere indicator of talent.

If you ask a billionaire the secret of his success, he might say it is passion, because that sounds like a sexy answer that is suitably humble. But after a few drinks I think he’d say his success was a combination of desire, luck, hard work, determination, brains, and appetite for risk.