What makes a good/bad teacher?

http://danceadvantage.net/2010/08/11/define-dolly-dinkle/

I had never heard of a Dolly Dinkle before, but it sounds all so familiar when compared to complaints and opinions voiced in the bellydance community. All artists have the same concerns...

One commenter wrote:

"Dolly Dinkle schools offer no technique or curriculum. Their schedule often reflects whatever is hot at the moment- lyrical, contemporary instead of ballet; all hip-hop; etc. 

Dolly doesn’t teach vocabulary or history of the dance forms. Ballet is not the only genre with this! So many students don’t realize hip-hop and breakin’ have a vocab and history! 

A well-rounded education: technique, history and vocab PLUS improv, choreographic, and performance opportunities makes a great studio."

Another poster commented:

We have a responsibility as teachers to keep advancing the field and ourselves through continuing education.  Since there is no standard in dance education, teachers have such varying levels of training, education, and certification. But as we all know, there are fantastic teachers with no performance experience, no degree, and no certification, and there are others who danced with ABT, have college degrees and five page resumes and are horrible teachers. It’s the teachers who continually seek knowledge and collaboration in the greater dance community who avoid pigeon holing themselves into a “Dolly Dinkle” atmosphere. 
For me personally, I think it comes down to motivation. When you sink into a routine and just “teach what you were taught”, that’s a tell-tale sign of my definition of a Dolly Dinkle. You have to continually analyze and assess: What are the needs of my students? What can I do to meet those needs? Is this a safe environment for my students? Is this a supportive environment for my families? Would I sign up my kids for my classes? It’s one thing to open up a studio with a concrete floor. Everyone has to start somewhere. But to ignore it for 10 years is quite another thing.This is fantastic! I think Maria made an interesting point about “teaching what they were taught.” We have a responsibility as teachers to keep advancing the field and ourselves through continuing education. The conference Nichelle is attending this week is a perfect example! Since there is no standard in dance education, teachers have such varying levels of training, education, and certification. But as we all know, there are fantastic teachers with no performance experience, no degree, and no certification, and there are others who danced with ABT, have college degrees and five page resumes and are horrible teachers. It’s the teachers who continually seek knowledge and collaboration in the greater dance community who avoid pigeon holing themselves into a “Dolly Dinkle” atmosphere.

And there are a couple other great comments in there as well.

What would you say is the mark of a good teacher? What were some traits of bad teachers you have encountered? And do you think there should be some kind of regulation? Why or why not?