It's basically true. I think thinking can be helpful for things that can't be acted upon right away...but I read this article just today about how 60% (and perhaps more, in the case of more complex problems) are solved spontaneously using "aha" moments. Oftentimes, these moments come when people are away from their typical environment because they mentally get themselves out of a rut. So when they return, they temporarily have a clear mind and can come up with novel solutions and ways of thinking about an issue. The article was advocating for avoiding things like checking your email, and dealing with mundane little old things when you return with a clear mind, because the resource quickly gets sucked up, you get back in the rut, and struggle to come up with new solutions to old, complex issues.
