That advice applies tenfold for entrepreneurship. Entrepreneurship is rewarding because it's a grind. If it were simply a gas, everyone would do it. Om Malik recently wrote eloquently about this on GigaOm:
If you don't find entrepreneurship a grind, you're not doing it right. The whole point of entrepreneurship is finding ways to do things that others consider impossible. That's never a walk in the park.
"The positive reviews and the buzz of the new release are going to last a few days, and then it will be back to the grind for him. The grind that consumes all founders completely. The grind that means managing a big company. The grind that means parting ways with your co-founder. The grind that means dealing with constant naysaying, haters and giants who exist to copy your ideas, poach your people and generally make you miserable.
Building things that are different, inventing the future and creating a real business is a long and often very lonely slog. But you don’t hear about that. Instead what you get is a lot of babble about startups from so-called mentors, advisors and startup gurus. Peel away their sharkskin and you find they have never started a company, and they continue to live in the reflective glory of the company that once employed them. Others are the creation of social media, having struck a pose. And some are born consultants. They find willing listeners among a growing army of entrepreneurs who like enterpreneurship as a lifestyle. Sorry guys, entrepreneurship isn’t a lifestyle, it is life."
This isn't to say that misery = success. There's a whole host of miseries that will hurt--rather than help--your chances. Infighting and wasting money are great ways to get miserable, but crappy for success.