I have been quite fortunate throughout my academic studies I think, and haven’t had many very demotivating experiences. However, I once took a course where the lecturer seemed spectacularly disinterested in our learning, used old material, presented slides that were difficult to read and that hadn’t been updated for a very long time, and although this is a long time ago, I remember being a bit shocked over how poor the lectures were. I was very interested in this topic but, despite this, found myself unmotivated and unable to waste any more time attending these lectures.
That was the first time I had felt that way during my undergraduate studies. So, my first reaction was to begin to look for an alternative course to take, but I really wanted to finish this course and learn this material, so the frustration was most significant.
Fortunately, I came across a book on this topic with problems and answers, and by working through this book, I felt I learnt something and was quite remotivated. Many of my coursemates really struggled with this course as well. The book I’d found, the lab practicals, and ad hoc study groups with coursemates saved this course for me.
I think if the teacher had made some effort to update the material, to carry out some formative assessment during the course, to break up the large classroom lectures with some exercises, and shown some interest in the topic, by perhaps linking the material (at least where possible) to current goings-on in the field and/or relevant industry, this probably would have sparked a lot more interest among the students, stronger motivation, and much better learning.
My interest in this topic was definitely dented and I instead went in a different direction during the rest of my undergraduate studies.