I was lucky to attend Y Combinator's annual Startup School this weekend. The event began Friday night with a party at the business school cum venture capital fund's headquarters in Mountain View, California, and continued Saturday morning with a talk by Y Combinator co-founder Paul Graham on the UC Berkeley campus.

Graham, whose ideas about low cost startups have launched something of a revolution in early stage finance (read about that here), gave a talk entitled "What Startups Are Really Like," that drew largely on the experiences of the hundred odd companies that Y Combinator has helped launch.

It's a long, 19-part essay that's worth a read for anybody who is getting started (or thinking about it), but perhaps the most interesting part comes at the end, when Graham tries to make sense of why so many founders find the process emotionally difficult.

The bottom line: Running a company is totally different from having a job, which makes it hard--and also interesting.

Money quote:

Everyone's model of work is a job. It's completely pervasive. Even if you've never had a job, your parents probably did, along with practically every other adult you've met. 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.

More here. I'll be blogging more about the what I learned at Startup School over the next couple of days.