I read somewhere that each and every one of us, unavoidably and involuntarily, affect the world around us. A seemingly insignificant gesture such as the flick of our finger can send microscopic ripples of energy across the cosmos, just as what we see when the surface of water is given that slight nudge. We physically see the ripples for a while which then fades into the microscopic domain before completely dying out. In the case which I stated earlier, that of the transmission across the cosmos, this may be very insignificant. The change or affect can be almost zero, but even then there is an affect; something that may not be discernible to the naked eye.
More than the cause and effect it is the thought that excites me. The thought of some alien being sitting many light years away suddenly finding inexplicable movements in its surroundings just because someone on earth, say, sneezed :-).