Read some Eric Berne books. Human interactions are practically built on pretense and games (and it is not always bad - actually, unless you are caught up in a self-destructive game, it often is good). Unless you're communicating with robots all day, truth is not exactly the primary factor here. Otherwise morning greeting would look like:

- I notice you! Here's some meaningless words acknowledging the fact. - I noticed you too. Please don't tell me anything about your life unless it's exciting but not making me envy you in any way. - Same to you, and please don't waste my time anymore now unless you are going to benefit me in some way. - I'm going to depart now, and I don't care how the rest of you day goes. - Neither do I for you.

I would submit a world like this would be perceived as utterly bizarre by most of us.