An MIT study on linguistic ambiguity concludes that the human capacity for disambiguation allows us to use simple linguistic forms to say a lot. Our ability to disambiguate depends on our mutual understandings of the contexts in which words are used. (Link: The advantage of ambiguity)
I have no argument with these conclusions, but do want to add that our dependence on mutually understood contexts very often confines us to conventional semiotic interpretations. This is fine in many social settings–academic, religious, professional, etc. But with close friends or loved ones, it is a formula for interpersonal disaster.
As mentioned in other posts, the fundamental ambiguity of so much of our interpersonal speech requires us to form interpretations of what others are saying to us based on lousy data. We have to guess what they mean through context, facial expression, tone of voice, word choice, etc. And this means we are very likely to form false impressions even of those who are closest to us. Our false impressions will invariably lie somewhere on the spectrum that spans conventional semiotics to private neurosis. If you are guessing about what your interlocutor means you are almost certainly going to be wrong.
Being a little wrong can be fine for a while but it rarely stops there. The vast majority of us keep adding to our mistakes, eventually creating deeply erroneous impressions of each other.