Can we really say those things?

I heard somewhere that an average person tells 10 lies per hour. I suppose thats when she/he is actually talking, although I know people who probably lie to themselves constantly.
My question is about the flip side to that number - what about the truths we dont talk about?

Is it possible to talk to someone and say "we both know there are rules to making things work - we both know them and eventually one of us is going to pretend they dont exist and mess things up"? Can we say those things?