Nobody wants to disappoint or appear unhelpful, but if you never master the art of the negative you’re going to find yourself spending a whole lot of time and energy doing stuff you don’t want to do. And, really, life is too short. Here are some polite ways of saying ‘Not on your nelly!’
Your sister has asked you to help her move on the day you need to study for a big exam. You’d love to be there, but are super-stressed about getting a good mark. It’s particularly tricky saying no to family, but even more important to stand your ground (and not to get guilted into things). Tell her upfront that you’re really sorry you can’t be there, but the second the pressure is off you’ll come over with a bottle of wine and lasagne. She’ll probably be a bit sulky, but she has friends who can help and, in this instance, your studies are more important.