Aliens (Not the Kind that Work at Walmart)

After watching War of the Worlds last night, I thought back to an old question I had about these types of "alien-invasion" scenarios: Why do we assume that if there is intelligent life out there, it's bound to be more advanced than us?

Fuck, it's just as likely that we're the smartest assholes out there. Where are all the movies about us invading some pathetic little civilization that's still stuck in the Stone Age? Good old-fashioned wars of conquest may have (temporarily) gone out of fashion on this planet, but what's to stop us from terrorizing us some E.T.'s? I want a little, green butler dammit.

Fuck it, time for lunch.