Elphaba, I was just going to get to that! Williams, and many others' stage directions are truly poetic.
Sometimes playwrights will add the production notes to the script after the original production as well--not so much to tell the actor what side of the stage to enter, but to clarify, or enhance the subtext.
Early works--like Shakespeare, yes, I can see directing "blindfolded". Um, still, you gotta read what's there!
"It's not so much do what you like, as it is that you like what you do." SS
"Time flies like an arrow, fruit flies like a banana." GMarx