As an industrial design student, I remember that I had a hard time during sketching classes. Not because I can’t doodle, but because I was asked to “sketch” and NOT to “draw“, which is quite a different thing.
Sketching is all about conveying the message in a quick and simple way; a tool designers use to quickly explore possibilities. And my biggest problem was always that I wanted to draw, to end up with a presentation drawing as close to my intention as possible, no room for error. I had the hardest time committing to a stroke because I felt it had to be perfect or not be at all, and of course I hated the fact that they were forcing me to sketch with ink fine-liners (not much erasing there I’m afraid…). It was quite frustrating and up to this day I’m bugged by it.