I bet this has happened to you. You meet someone who has bad energy: vindictive, passive/aggressive, bitter. And then you find out their profession: yoga instructor!!!
All of us have bad days and bad moments. Regardless, when you meet a yoga instructor that has these traits, how can you take them seriously as a yoga professional?
I don't practice yoga, but it seems obvious that you want to create positive energy, unity with self, etc. Another example: an obese person selling health foods.
Whatever your profession is, picture the behavior of the top performers in your field. How do they act and feel? What impressions do they leave on other people?
Become aware of how you are perceived (I had to ask people) and adjust accordingly. In the long-term, aligning your behavior will pay dividends.