I've seen a lot of essays claiming to explain why privacy is important even if you 'have nothing to hide'. They all fail because you manifestly don't need privacy unless you have something to hide.
The truth is, laws are written by ignorant mobs and we want to break them. We want to try marijuana, exceed the speed limit, rip DVDs we bought to an archival format and occasionally share them with friends, use incandescent bulbs because they provide better light and alternatives are provably no better for the environment, and fix our shower faucet without having to apply for a permit first.
Privacy is a natural foil to legislation run amok because it lets us break bad laws. It helps ensure that laws really do require the consent of the governed. There's even virtuous feedback, since lawmakers have enforcement budgets and need to appear effective.
So yes, I have something hide. If you need to see inside my house, it's a good sign the thing you're trying to prohibit isn't harmful enough to society to warrant the force of law.