My latest read is a fantastic book by Professor Damian Hughes, Liquid Thinking. It has the premise of being clear about setting targets, surrounding yourself with like-minded yet driven people and ensuring that your beliefs affect your behaviour in the manner you want them to. He discusses the concept of Possibility vs Probability Thinkers, in reference to those who are "Yes and..." vs "Yes but..." people. I know I have been more a probability thinker in the past - looking for potential pitfalls and sizing up the chance of things going wrong! Hughes asserts that we need more Possibility Thinkers - those who stand with you and your dream and believe in you.
I think his point is not that we should be overtly optimistic (although Duckworth and others suggest that this is a fantastic trait to have) nor should we be dramatically pessimistic. Perhaps it is all in the balance again - when you are formulating a dream you need both types of thinkers to shape it and make it better. When you get on the journey, you need both too - people to help you refine when things don't go well and realign when you've lost focus. However, too many times we fall into the trap of sticking with too many Probability Thinkers or Dream Snatchers as another called them. I want to be a Possibility Thinker for myself and others. Who do you have that is standing with you, spurring you on?