As an old guy, let me share with you which of these I think was the biggest lesson for me:<p>-- We do not need to be lead by business people.<p>MY new rule for startups - the big engineer should be the CEO.    You can have a CTO and other engineers.  You can have a VP of bizdev or sales.  But the big fish needs to be an engineer if you are a tech company.  If you are making biotech the big fish needs to have biotech engineering.  If you are manufacturing, then the big fish needs to be a manufacturing engineer.<p>The number one mistake I see startups make (especially when they are started by younger people) is taking some type-A business school graduate and making him the CEO.<p>This is the cause, ultimately, of most of the failures of startups I&#x27;ve experienced (and I&#x27;ve worked for, founded or worked with a couple dozen.)<p>Or, as a second order function, type-A business school graduates who have never started a company or worked a real job but do instead work for a VC firm, forcing bad decisions on your company.<p>Most of the fights between founders are because business guys are forcing bad decisions on the company.<p>The problem is, business school doesn&#x27;t teach YOUR business. It teaches general business concepts. These are not difficult for engineers to master.<p>IT&#x27;s impossible for these business guys to master engineering.  (Yes, 30 years, still haven&#x27;t seen that- the best ones just find an engineer they trust and get out of the way.)<p>As an angel investor, if your CEO isn&#x27;t a geek, I&#x27;m not putting my money in.  And if you look at the &quot;successes&quot; where this is the case, it&#x27;s usually an arbitrage opportunity (Eg: somewhere just piling a bunch of money behind a halfway competent business model with half way competent employees is going to make money because the situation is the result of a structural inefficiency, usually caused by government: uber for example.)