When someone asks you to do something and you say “I can’t,” what you actually mean is that it’s not your top priority. But you sound like a jerk if you say “No, that’s much less important than what I was already doing.” When you say “I can’t,” they get the benefit of not having to think you’re just blowing them off, and you get the benefit of setting your own priorities. It’s the perfect little social nicety.

Like all times you blow people off, make sure you’re using it responsibly.