Lots of "software" companies are just as political as big corporations, and startups in particularly are often much more chaotic/stressful and offer far less job security.

Notwithstanding the fact that a ton of companies that would like to believe they're "software" companies really aren't, the high turnover at Silicon Valley firms suggests that working for these types of software-centric employers isn't the happiness panacea you make it out to be.