I worry that between now and full self-driving there will be an intermediate stage in which the human driver is the slave of the car. - Paul Graham

So although there may be, in certain specific moments (like your family, this month) a fixed amount of money available to trade with other people for things you want, there is not a fixed amount of wealth in the world.

When startups fail the reason is almost always that they haven't made what people want.

To write good software you must simultaneously keep two opposing ideas in your head. You need the young hacker’s naive faith in his abilities, and at the same time the veteran’s skepticism.