I started to learn to fly when I was 19 and gave up when I was treated badly by a new instructor. He took me for my first nav ex and turned me into a nervous wreck. Tutting, shouting, barking orders etc.. This 40min introduction to NAV felt more like 4 hours. The strange thing was that after we landed he commented on how well I'd done...? It didn't matter though, I went home feeling crushed. It was the worst lesson I'd ever had and he was only supposed to be showing me the techniques used for navigation.
Anyway, it was nearly 4 years until I decided to give it another go. This time I went to a different school. I had 2 instructors from start to finish, and they were brilliant. They gave me invaluable advice, criticised where necessary but above all gave me the confidence to fly well and pass my skills test.