It's useful to understand the natural flaws in the human mind, like the tendency to be risk averse, avoid uncomfortable situations, not be present, which can keep you stuck. Some of the PU material can provide tools but too much theory can get you confused and in your head too much when starting off that will cause you to screw things up.

I think on some level most guys have the innate knowledge to do the right thing at the right time. When there's no thinking involved it's simple. What you want to do is bring that out of yourself more rather than, as Stein says, adding more mental clutter.