Something I explained to 12 yo: The biggest startups are always where two basic forces meet. E.g. Facebook = social relationships + internet. But these ideas are rarely found by looking for such intersections. They start as side projects you only later realize have this quality.

One exception is Amazon, which Bezos started after he realized the internet would be a powerful force and asked what he could intersect it with.

YC is at the intersection of venture funding and mass production. We realized this a few weeks after starting it, but it was not our original motivation. Originally we just wanted to make it easier to start startups.

One of the first things I do in office hours with a startup is try to figure out what basic forces the startup is or could be at the intersection of. It's a useful thing to know, as well as a good first approximation of potential.

Founders who haven't consciously thought about their company in these terms are often surprised and delighted to hear they're doing something more important than they realized, and leave feeling full of ambition. But this is not mere pep talk. It's the truth.