Have you ever worked with someone who did not give you a sense of comfort or safety? Good instructors are very safety concious, they are confident, they may not know all the answers but will not BS their way through an answer if they don't know.
A student of mine, who is a sweet lady, recently had a trip to a range with a group she is affiliated with. The instructor gave them a range brief that apparently left more questions than answers. There were people handling firearms in the classroom with no regard for safe direction (I've accidently been muzzled, I don't like it either, even if the gun is unloaded) and the instructor / RSO just ignored it. Apparently range rules were not well enforced, safety was lax...suffice to say, she decided it was not a good environment for her.
She did the right thing, she left. A good instructor can make your shooting experience comfortable. A bad one can make it scary! If in doubt, leave. You know if you don't feel safe, trust your instincts and stay safe.
I was really proud of her for trusting her feelings instead of staying in what sounded like a bad situation.