It's funny thinking that what you say is totally different from what they think you mean.
Sometimes you just step forward and start talking. No pretensions, no requests, no actual necessity - you just start talking. Of course, nobody will listen to you because they didn't ask you for anything. So, in that case, you're pretty safe.
The problem begins with involvement. When someone finally decides to listen to you - either because she asked for it, or because she just doesn't have a choice - you're in it for the long run. What you say will be taken as it is, and that's how it's supposed to be. It doesn't matter whether you don't really mean what you say, or whether everything you're spewing out doesn't involve much mental activity. The most important thing is, what you say already speaks for yourself.
The bigger problem begins with you getting caught. Provided that you didn't mean everything that you said, and that something awful - that doesn't give it justice, but oh well - happened, well, you know what happens next. Aside from not being trusted with everything you say - "kalokohan 'yang sinasabi mo, kasi hindi naman 'yan talaga ang ibig mong sabihin
" - you're going to make a mess out of trying to be understood. Provided that it's related - and it will always be, if you ask me - they'll think of that big cock-up. That's all that they will think of.
It's been said that first impressions last, but when do we really start doing that first impression? Is it that one, memorable moment when you finally decided to define who you are? But if we keep on defining (and redefining) ourselves with everything that we say, and eventually, everything that we do, then perhaps it's not us who chooses what we are, but them. Say, after three years of being the nicest person in the world, you snapped and got angry, and she'll think of you as someone who refuses to cooperate. Or, after ten months of being charmingly naïve, you speak out about your frustrations with the world and start pointing fingers, and she'll think of you as, well, a real estate agent selling the black hold so that he can have a neighbor. No amount of deodorant can clean that up, because it will last.
So, is it better if you just don't speak up? The world rewards those brave enough to talk, but punishes dissidents of every kind, from the obvious to the subtly unrelated. The best advice I can give you, then - without selling a black hole, because I just moved out, but perhaps it will never get scrubbed off - is this: don't bother.