astronomy11, I don't think anything is critical to the system (I'll take flack for that
). Most of these things come in degrees. It's not I'm relaxed enough or I'm not relaxed enough. It's the more I don't worry about it and the more mentally and physically relaxed I am the better it is. Stress and fear create physical barriers to you thought pattern. You are striving for you optimal brain use. If you are running and try to run your fastest, you may not run you fastest for many reasons including trying too hard. However, you are still running.
Same with all the steps of the program. Paul tries to lead us to place were we can achieve our personal best. If we don't quite get everything right, we don't do our personal best.... be just do the best we can at that moment. Playing with it is important, because by using it you will discouver your how to create the fluid and efficient results. It's natural to figure out how to do it.
You've got to watch out for you negative thoughts and doubts. Those are the almost invisible barriers that can stop you from achieving your goals. With what Paul has given us, it's only us that can bring it to fruition or kill it.
I better stop now before Yoda starts piping in. 
Iam2 
