When you're given an opportunity-whether it's a promotion, potential customer, or learning experience-the most natural response is to say yes. Why not accept a higher salary? Why refuse a chance to study abroad? The reality, however, is that most of us say yes too much, too quickly, and without enough thought. We're wired to please others, and we've been conditioned to think all opportunities are good things. So instead of always saying yes, ask yourself these five questions first.