The observer effect
If I understand quantum physics correctly, observing counts as creating entanglement between the observer to the observed.
Whatever you experience is in part your decision and your surrounding’s existence. Take instance, you are reading this article because you have decided earlier to read it. The article itself decides which part of the reading surface may emit light. So it feels kind of stupid to even consider the question “Did I cause [something] to happen?” If the answer is not obvious, there is no point over thinking it, since a part of your experience has to do with your decision anyway.