In theory I was a good driver, but I always went all nervous whenever those instructors were sitting beside me. :rolleyes2
So I failed the first one, but that was mainly because I disliked the instructor.
Then I got another one, and he rocked; he was calm all the time, and didn't have this "ahem, do this right" attitude, but more like "yes, we're gonna drive, just relax and have fun".

I think the way you get along with your instructor is very, very important.