Why do we not say what we mean?

That usually happens when I'm really, really nervous. Everything just flies from my mind. But like you said, even we do say what we really mean, we still can't predict the other party's response. Sometimes I prefer to go with the flow and not pressure myself too much thinking about what I have to say.

This is so true!! I guess it happens because deep down we feel that it may hurt others!! For example, if I am angry at someone who is close to me and I have thought what I want to say, but the moment that person comes I will not say it, and will try to say it as the conversation goes , thinking that I dont want to be harsh!! Or, if I am having a crush on someone, an I am rehearsing that this is how I will approach, but the moment that girl comes I will stutter and not say thinking what if she hurts me or worse , starts hating me!! LOL I guess it is just our subconscious that avoids us from saying it!!

I hate this when it happens. Much like the scene in 500 Days of Summer where the guy's expectations didn't turn out the way he thought it would. Tsk.

What good are all those rehearsals then except to practice what might happen.

Here in the south (USA) we sometimes have a problem telling someone "no." We can say"yes", but it takes five minutes to say "no" and to explain why we're saying "no."

Poetry is eternal graffiti written in the heart of everyone.

Sometimes it's fear. We may be afraid of their response. We'll never know if we don't communicate.

I rather like written responses, you may lose body language and tone, but you have longer to formulate a response