Paul Graham on what’s so different and mysterious about starting a startup:
The key to that mystery is to ask, how different from what? Once you phrase it that way, the answer is obvious: from a job. Everyone’s model of work is a job.
Unconsciously, everyone expects a startup to be like a job, and that explains most of the surprises. It explains why people are surprised how carefully you have to choose cofounders and how hard you have to work to maintain your relationship. You don’t have to do that with coworkers. It explains why the ups and downs are surprisingly extreme. In a job there is much more damping. But it also explains why the good times are surprisingly good: most people can’t imagine such freedom. As you go down the list, almost all the surprises are surprising in how much a startup differs from a job.