In my opinion its ME...bear with me, its not actually me that's stopping everyone LOL. Look at it from your perspective who is ME. Many pupils struggle not because they have been a bad driver or 'cannot do it' its because at the end of the lesson, they focus primarily on what they did wrong on that lesson.
The ME part of you says something like "Oh my god, I cannot believe you stalled at that junction. Your so embarrassing" what the ME part is forgetting is this. You did 50+ junctions before that mistake and another 20 after with absolutely no issues at all. So think about that. 1 in 71 junctions weren't good. Now flip it. 70 out of 71 junctions were spot on. So in actual fact 0.014% of junctions you made a mistake. Is that all? Dude your awesome. How many full licence holders still stall? I know I still do on occasion. It just takes a short lapse in concentration.
In my car there are no faults or mistakes. I call them learning
opportunities :) if you have a learning opportunity arise in the car, think about what you misjudged and learn from it. Maybe you didn't apply enough gas on this junction. Maybe you lifted off the clutch a bit quick. Analyse it. It only becomes an issue because the ME part of you is your own worst critic.