Yes. People who have black and white thinking are generally rigid, lack in flexibility, lack in creativity, and they very often have interpersonal difficulties because of a difficulty in problem solving and perspective taking due to a narrow way of thinking. Look up cognitive distortions.
Absolutely not. View the world however you want to. If that view is only "black and white", there's nothing wrong with that. If there are "shades of grey" that's perfectly fine, too :)
There are always shades of gray in everything you do, it is up to you how far you will go, cause once you go in that grey, that will expected of you.
When things are always black and white, you tend to miss out on the more valuable shades of grey
then what you you call valuble shades of grey?
Grey can also be morals, service, etc.