TL;DR When you face a problem, don't overthink. Just do it.
During my PhD, I fell several times in a very annoying spirit, totally messing up my critical thinking and my creativity. I was unable to progress and go beyond the issues I then faced. My productivity dropped and the caused unproductivity just reinforced this bad spirit. It was a very bad feeling. I was just demoralized, and it could have been worse. It was impossible to progress like that, and I tried to find a solution.
First, I realized the basic reasons behind: the project became too personal. It was at a point that I mixed up my personal development with the project achievement . It was not so illogical. I spent most of my time on the project, even having some thoughts running in background during my "free" time. Second, I wasn't alone to experience this: other PhD students, but also simply other persons involved in creation or development. This simply helped me to play down. I just needed to step back, took some distance. But how?
I was and I'm still a frequent player of any kind of games, especially board and video ones. It is usual to experience hard situation, in other words hard to resolve or to win. But well, it is always easier when it is not about real life. Moreover, it's just a game. I simply enjoyed it and tried to do my best play. It inspired me. I've tried to do the same with my personal situation. And it worked.
It helps me to step back and take a better perspective on my work. The most important, I've realized that anyway you can experience something bad, it just doesn't help you to prematurely think too much about. At the end of the most of the cases, the consequences are not so terrible and you've probably learned something by doing it.
It worked and it still works. As a young startup, we have our own set of questions and challenges, from cash flow to market validation. I see this way of thinking helps: see what you can do, do not delve too much into the multiple possible outcomes and act. I don't overthink the consequences, and I just focus on the problem, considering it as a challenge, a game to resolve. As Yoda said:
Do ... or do not! There is no try.
And you, how are you coping with this kind of bad spirit?
Update: About the same topic, there is a more developed blog post What’s The Most Difficult CEO Skill? Managing Your Own Psychology