I tend to think of various complications and what-if's, so I often have a hard time making a quick, clear, black and white decision.

In one way, I can see black and white thinking as anxiety related because it's like you have to make an immediate decision instead of relaxing and taking your time to consider all the possibilities. For example, one of my coworkers the other day got up and started announcing a new policy she was working on. To me, it was obvious that it would work a lot better if she took time to gather more feedback from the whole group. But she tends to be a very black and white, cut and dried thinker. Whenever questions start arising from people, she cuts it off and uses her loud voice to insist on her perspective of "the way things are." I think it's easier in her mind because she's anxious about taking the time for a conversation that would let everyone discuss and understand many possibilities. The discussion could lead to a policy that actually works well, but she's probably anxious it would take more effort to come up with a decision.

On the other hand, thinking of too many possibilities (shades of gray) can also be due to anxiety-- anxiety about finally making a decision. So I think either extreme can be a problem.