The Cult of the Good Student.

You can come across Tai Chi instructors who will single you out as a Good Student. Or a Good Chap / Girl. Or you have Good Energy.

Sounds good, doesn't it? We all like a bit of praise.

But it is flattery. The " Good " label only lasts as long as you go along/agree  with or help the Instructor.
It is a form of manipulation. If you no longer "jump" or respond as expected you are quickly relegated to the " Bad " student category. This can cause you to become disheartened and possibly give up your Tai Chi. If you are still there the Instructor will get round to you again to give you the chance to become a "Good " student. And so the cycle continues.  It  has a taste of Pavlovian conditioning about it. I also believe it stems from some form of insecurity on the part of the Instructor.

As an Instructor one should strive to avoid labelling. All students are on their personal journey. They may continue to study with you or not. This is the natural way. You do your utmost to teach everyone what you understand to the best of your ability. Learn from all students. It's a two way process.

For further reading, I suggest Martial Arts Madness by Glenn Morris, Chapter 4 - The Gurus of Death Archetypes.