how would people act if there were no such thing as emotions? what would the world be like? the government structure?

No pain?

We'd be like Vulcans, and we would most likely be able to govern ourselves anarchistically through direct democracy.

~Simone,
       Live long, and Prosper.

There would be no emotion, for emotion is but an opinion of your thoughts. Emotions are what it means to be human; people that don't experience emotions are basically psychopaths. As far as government, there wouldn't be any, for the government is in place to protect us from ourselves, and without emotion no one would be harmful. And the world would be an eco-society of lifeless shells, where it seemed as if everything were "perfect".

tink

Ever read the book "1984" by George Orwell?  That's how I would imagine life to be like if such situation existed.