Working at Google or other well funded, yet young technology-at-the-core companies (which includes some startups too) means you spend most of your work hours do

Working at Google or other well funded, yet young technology-at-the-core companies (which includes some startups too) means you spend most of your work hours doing what you enjoy: coding, code reviews, etc... On top of that, evenings and weekends are yours: if you don't get a chance to learn tools, technologies or concepts you're interested in your work hours (and if you chose the right place, you frequently do) you can do this on your own time. You also get to work with plenty of people smarter and/or more experienced, which is a great way to grow professionally. Starting your own company (or joining a very early stage startup) means you'll be spending only a small proportion of your time coding: if all you do is as a founder is write code, you're essentially guaranteed to fail. Certain kinds of problems (core web search algorithms in post-Google era being the obvious one) are also, traditionally, are much more difficult for small startups to tackle than they are for big companies: certainly if you're passionate about these kinds of problems, than startups are generally off the table (in this case, your opportunity cost is much higher than money). Obviously, it's still extremely rewarding for many people (it's something I'm still interested in doing at one point or another), but "start my own company" vs. "work at a great technology company" is neither clear cut in favour of the former nor mutually exclusive (witness "Xoogler" startups, Paypal Mafia, etc...)