
Maybe its a subconcious thing? When you're just out cruising and managng your ride, you can be deliberate in your inputs to the bike because you are working on a smooth muscle memory mode with less concious thought.
But if you start thinking about doing each input correct "Ohh my gosh, I hope I don't mess up ___ as I have to get out of the car's way" then I think you jinx yourself and the concious effort on the inputs actually reduces the smoothness and force from a solid strong action.
I guess it pretty similar if you scutinize a technique that you do regularlyand all of a sudden you can't do it right because you're thinking about it too much.