Slagging-off your instructor

 It is common for students to leave a martial arts class and then broadcast a list of criticisms about their former teacher.
This not only reflects badly upon the ex-student but also makes them look kind of stupid:

 • Do you consider yourself to have skills?
 • Did you have these skills before joining the class?
 • Who taught the skills to you?
 • If your ex-teacher is a fool, then what value does their teaching have? What value do your current skills have?

To criticise your former instructor is to devalue what you were taught.
If your current understanding is based on what you were taught by your former instructor, then to criticise your former instructor is to undermine your own knowledge and skills.
Your own skills are the product of that tuition.
If the teaching was worthless, then what you now know is similarly worthless, and certainly not worth listening to.

If you learned your skills from your former instructor, then they must have taught you something worthwhile.
For this alone, you owe them your respect.