I can tell you from personal experience how: If you take literally the advice of investors and startup-ra-ra types and put everything on the line for your startup, your own money, your time... and then something like the financial crash of 2008 hits just as you're raising your round, your $500k Salesforce.com pipeline of business that depends on marketing spend from big corporates in q4/08 and q1/09 collapses and literally 0% closes... You get divorced. Being broke isn't a bonus feature of the startup process. It can be an unfortunate side-effect and one that takes some effort to dig out from. You'll make it out again if you stick at it, but it's not fun and it WILL cost you things in your life that are important to you.

Remember, families didn't sign on for your start-up dream. Not being able to pay the bills is not cool. It's bad advice from people who've either never honestly been there, or folks who've forgotten what it was like there and are romanticizing it, or folks who are insecure about their success and want to build a struggle-against-adversity narrative to feed the myth of the hero-founder.