The balls hit grooving a tempo is a big difference between the Tour Professionals and the rest of us Professional and Amateur alike. However, there are certain other things that affect your tempo. Have you ever noticed how a professional (Phil 2003) with something difficult going on in his personal life doesn't play as well (lack of concentration). Think about what you have going on when you aren't relaxed and playing well...maybe a problem at work or you got a late start and rushed to the golf course and to the first tee without doing any of your normal routine prior to play. Even what you have eaten/had to drink can affect your game...too much caffeine and you are wired for sound. Funny story about that...I used to play with the members at my first Head Professional job every Sunday at 8:00am standing tee time. One Sunday I got there really early and was at my desk doing some work and eating brownies and washing them down with Pepsi. I was so wired at the first tee that I didn't even get the club much past parallel to the ground, much less all the way to the top. I think it took 4 holes before I slowed down to a good tempo but it illustrated the diet point quite well to me.