1) Buffett has a rare mind for numbers and the ability to see through accounting statements to what's actually happening with a business. He's able to focus on actual evidence rather than resorting to guesswork. So many investors operate on guesswork and speculation.

2) The moat concept, but a lot of people get it totally wrong. Technology seems like an obvious moat, but it's constantly evolving and rarely provides a durable moat. Moats can be simple things, like brand value or network effects. These days building a worldwide brand is not easier than developing a new smart device.

3) His BNSF railroad purchase was surprising at the time. Everyone was focused on tech and finance, but he identified a rare undervalued asset. A rail network and property rights supporting it are not easy to build these days.

4) After studying Buffett, I realized that return on capital is an extremely underrated metric. It's a great way to find better companies within an industry and for spotting smaller firms taking share from bigger, less efficient players. It's so common to see stock fundamentals reduced to a growth vs value dichotomy. Buffett understood "quality" and return on capital is one of the best indicators of it.

5) They avoided trading based on hype and momentum. They were patient and waited for incredible bargains rather than riding the coattails of someone else's trend.