David,

Yes, I would have said that his demands were unrealistic!  A

I have not terminated a listing agreement because I have not had to yet (crossed fingers). If I were to run into a so-called jackass, I certainly would have no problem terminating the listing agreement.

Only had to do so with a buyer.  I did have one listing where I seriously considered cancelling and the next day we got it under contract, so it was worth holding on to 

Not yet...wanted to, should have gotten a clue when replacing burned out lightbulbs was just too much work.

Well, I certainly had situation when I wanted to walk away, but usually we find a solution to our differences or misunderstanding.

I remember I fired my buyer once, she became very close friend and wanted to take advantage of our friendship.

Not yet.

No, there was one that I should have.  

Yup!  If working with a client is well, "not working"...and I can't see my way to a successful transaction I have learned to bow out gracefully with the line..."I am not the right agent for you."

I guess I've been really lucky. I've pretty much had good sellers and I haven't had to terminate them. 

Yes and I would do it again. Same goes for buyers. 

I never had a client that was a 'jack ass', David.  Though I have terminated listing agreements because we just weren't a good fit with each other.

Yes.

Oh yes!

Yes, several times.

I have not gone that far, yet!