The Introvert's Code of Conduct
Article 2: The Art of Saying 'No' (Without Apologizing For It)
Rule 1: You do not have to explain, justify, or make up some half-baked excuse for saying no. A simple 'no' will suffice.
Rule 2: If someone asks why you're saying no, you can say 'I'd rather not discuss it' or 'I'm not comfortable sharing that information.' End of story.
Rule 3: Do not, I repeat, DO NOT, make eye contact or pretend to care about the other person's feelings. That's just extra work.
Proceed to Article 3: The Joy of Being Alone Or, if you will, Article 4: The Futility of Apologizing