Clarity in writing and speaking is something I strive for. I learned when I was teaching that if you don't give students clear instructions, they won't do what you want them to do, and that is your fault, not theirs. I also learned that some of my colleagues were not as careful as I was: part of my job was to help students with written work, and even though I had more experience of reading between the lines than them, there were still occasions when neither of us could work out what it was they'd been asked to do. How do you tell a colleague that what they have written doesn't mean what they think it means – or worse still, is incomprehensible?
I have given up buying needlework magazines, because so often their instructions are unclear – or downright wrong. Textile books are usually better – but not always. I am experienced enough to know when something is wrong, and how to get round it, but even so sometimes I'm stumped, because the instructions are so unclear. I think proof-readers and editors must be a dying breed.