I learned that I will always add, "If any area was rated less than 5, what could have been done differently to improve this rating"?
This is a good practice.
When I have done presentations, I have asked, "What, if anything, would you do differently to improve this class?" The responses may give you valuable feedback and good ideas. They may also tell you the mindset of the responder and how much credence to give them.
If the answer is, "eliminate it," or, "cut it to fifteen minutes," or, "pass out Hershey bars," you can surmise that you are dealing with someone who just didn't want to be there, period. I wouldn't worry too much about that attitude, as there is little, short of canceling the class, that would please such a person.
When you get serious answers, such as, "Provide a handout of the most important points," or "Speak slower and louder," you can focus on specific actions (and their possible remedies) rather than whether people liked or didn't like you
It doesn't pay to take these things personally, especially when you have such a wide-ranging group that, by its very nature, will include people with varying levels of investment in being there. You only set yourself up for disappointment and harsh self-criticism if you don't place limits on what you will absorb. Asking for specific feedback with
suggestions for improvement should help you distinguish between whiners and those with legitimate criticism. In neither case should you allow yourself to make it about you, only about what was done or not done.
I wish you the best.