I wrote some piano music recently, and had my students perform it in a concert. Gosh! I was much more enthusiastic about drawing their attention to the details of the score than I usually am.
I am vexed by students who are unobservant. I ask them to reconsider their prospective job choices, and advise against being a detective: since both the performer and the detective look for clues.
Sticking with the jobs analogy, I explain to my students that I am not a magician – when I know how something goes and they don’t, mostly I am simply reading what it says on the page. I often don’t have any more knowledge of the piece than they do.
I do remember, in the dim and distant past, my own piano teacher (who was married to a Very Famous Composer) remarking somewhat drily that it takes longer for a composer to write down performance directions than it does for him to miss them out: the least a performer can do is not ignore them.