Here's something a lot of entrepreneurs don't know about business plans: they shouldn't be all sunshine and happy talk. Sure, your business plan is a sales tool. And it should highlight your start-up's strengths, what makes it different, and how it will be profitable. But, you also have to recognize that your business won't operate in a vacuum. Too many entrepreneurs crank out business plans that floridly talk about how the company will raze the competition and will become a tremendous success with vast profits while ignoring the obvious—areas where they're weak. While it's terrific to talk about where your start-up excels, and, hey, that's what your business plan should do, it doesn't hurt to mention areas where you don't.

Now, before you fire off any emails telling us that we've lost our minds, hear us out. Getting the bad stuff out there makes you look good. No, that's not crazy double talk. The reason why spilling your weaknesses can actually help you is because it shows you're aware of your business' shortcomings. And if you're privy to them, that means that you're devising ways to tackle them. Putting your weaknesses out on the table also shows an investor that you're honest—and that you're not trying to hide anything from them. Trust us, investors do their due diligence. They'll turn up where you're weak, and where your competitors are stronger. No start-up is perfect or infallible.

So, why is it that so many entrepreneurs ignore this simple fact?