1. You won't be your own boss. Yes, your customers will tell you what they want, but ultimately YOU decide the direction of your product/company. In this sense, you most certainly are your own boss.
2. You won't like your personal life. Unless you are passionate about what your business, and you love what you are building. Also, this is empirically and anecdotally wrong.
3. You won't succeed. Every startup fails for one reason: the founders quit before they build something people like. There is no other reason for failure (esp. in the case of software). I will defend this point separately, if need be.
4. You'll hate the problems. By definition, problems are problematic. But the problems you are trying to solve in YOUR business will be a lot more engaging than the trivial problems you are working on in a large company.
5. You'll be a jerk.
I don't even know how to respond to this one. Have you ever worked in a big office? Go to passiveaggressivenotes.com -- I bet that 99% of the content on that site comes from cubicle-style offices.
6. You'll hate your lifestyle.
Empirically wrong. It's a challenging lifestyle, but whether you hate it or not depends more on your personality type than on the lifestyle itself.
7. Again, you'll fail. c.f. 3