I understand you. All the long ours in preparation, planning, interacting, evaluating, and for me, the compensation for all that was quite ridiculous to tell you the truth. Students only interested in the course's diploma, asking questions like 'why am I seeing this?', 'how to apply this in the real world', 'give me a practical example in your practice' (knowing that I was only a lecturer, not a practitioner in the field, the list goes on and on. I don't miss being on classes - what I miss is interacting with good smart students, to tell you the truth. They were the ones I target my efforts. Your reason may be other, mine was this.