Why "Why not?"

Why did I choose this name? Well, why not? OK, OK, I'll explain. Many people, when they are asked (for) something have a tendency to automatically respond in a negative way: "why should I do this?", "why do you want that from me?", "what's there for me to gain?", etc.
I want to propose a reversal pattern - when you're asked something and you want to say "no" or "why?", start by asking yourself "why not?". In most cases, you'll find out there are at least as many and as good reasons for a positive than for a negative approach.