Hey hi Miguel,
I totally agree with you : taking pictures of people dancing is quite a challenge! That's what I've been doing for 8 years now and I'm still learning as it's different with each dancer.
I do everything in manual mode and I never use the continuous shooting mode : for me, the challenge of pulling the trigger at the exact moment as you anticipated the dancer's movement is the thing that I really like in it. I never use flash during the day because of the special type of pictures I take (IR) but I understand what you mean.
Taking pictures of people who don't want it is really tricky, even if you're covering an event. Fortunately, I don't have to deal with that as I always work with persons who like it a lot and they ask for it.
People who use your photographic work without giving you a shout out is something very rude the way I see it : you gave time and efforts for them and they just have to mention the author : you. This is a steal, it's tolerated for photography and that's one of the many reasons our art is so devaluated nowadays.
Thank you for sharing your experience with all of us :)
You are so right, you can apply all your knowledge and still not get a good photo. You have to shoot many times with your camera. Of course, the knowledge I share here can help you, rather than hinder you in your goal of getting a great memory.