PayPal's Co-founder Peter Thiel Discusses Startup Success

As the co-founder of PayPal, Peter Thiel is one of the biggest entrepreneurs, venture capitalist and hedge fund manager in Silicon Valley. The New Yorker called him one of the most successful technology investor in the world.

He's well-known for giving Harvard drop-out Mark Zuckerberg a half-a-million-dollar loan for 10.2 percent of the company. Today, his Facebook shares are worth about 1.5 billion dollars today.

Late last week, Thiel spent a few minutes fielding questions from Redditors in Reddit's famous "Ask Me Anything" series.

Thiel offered fascinating insight into random topics, including the start-up scene. Here are some highlights.

On Thiel's biggest investment mistake:

Biggest mistake ever was not to do the Series B round at Facebook.

General lesson: Whenever a tech startup has a strong up round led by a top tier investor (Accel counts), it is generally still undervalued. The steeper the up round, the greater the undervaluation.

On not investing in founders who wear suits:

No absolute and timeless sartorial rules.

But, in Silicon Valley, wearing a suit in a pitch meeting makes you look like someone who is bad at sales and worse at tech.

On a rumored ban on hiring MBAs & the state of K-12 education: