We don’t need to explain ourselves to others all the time, and especially when we’re asked a favor and have to say “no.” You are justified in merely saying “No,” or “No, thanks,” or “Sorry, I can’t.” You owe no explanations when you refuse someone’s request for your time, money or energy. The more you explain, the more you’ll weaken and ultimately accept.
Mindset: You have the right to remain silent.