My science teacher in Junior High School, Larry Little, told me the most important thing I ever learned in science, "DBK".
In Larry-speak, this translated as, "Don't Be Knowin'", or, "Science hasn't figured this out yet."
It was even a valid answer on tests. He would ask some yet-unanswered simple question, and the right answer would be "DBK".
That has stuck with me throughout my life... that there is stuff that science just doesn't know... yet. And, throughout my life, some of the DBKs actually have answers! Like "are we living in an inflationary universe, or not?", and other simple things we still don't have good answers for, like "when are you dead?", or "why do we dream?"