(Paul Graham) One of the more surprising things I’ve noticed while working on Y Combinator is how frightening the most ambitious startup ideas are. In this essay I’m going to demonstrate this phenomenon by describing some. Any one of them could make you a billionaire. That might sound like an attractive prospect, and yet when I describe these ideas you may notice you find yourself shrinking away from them.
Don’t worry, it’s not a sign of weakness. Arguably it’s a sign of sanity. The biggest startup ideas are terrifying. And not just because they’d be a lot of work. The biggest ideas seem to threaten your identity: you wonder if you’d have enough ambition to carry them through.
There’s a scene in Being John Malkovich where the nerdy hero encounters a very attractive, sophisticated woman. She says to him:
Here’s the thing: If you ever got me, you wouldn’t have a clue what to do with me.That’s what these ideas say to us.
This phenomenon is one of the most important things you can understand about startups.  You’d expect big startup ideas to be attractive, but actually they tend to repel you. And that has a bunch of consequences. It means these ideas are invisible to most people who try to think of startup ideas, because their subconscious filters them out. Even the most ambitious people are probably best off approaching them obliquely.
The start-ups? Here’s a quick glance:
1. A New Search Engine
2. Replace Email
3. Replace Universities
4. Internet Drama
5. The Next Steve Jobs
6. Bring Back Moore’s Law
7. Ongoing Diagnosis
They seem pretty straightforward until you think about what they mean. One might argue that the big ideas are like a good ending–inevitable and yet unexpected. Read the whole article here: http://paulgraham.com/ambitious.html.