Why do you think being polite can sometimes get you better service than being aggressive or demanding in high-pressure situations?

Have you ever served on a jury where the case got dismissed unexpectedly? What happened?
Can you share a time when you were surprised by the kindness or generosity of service staff, and what you think led to it?
Why do you think some people resort to being rude or aggressive when trying to get better service, and does it ever really work?