I have had many teachers since I first started playing.... I should try to count... four teachers while I was in Japan... seven since moving back to the US. That might sound like a lot, but that's over the course of 25 years now. Only three of these teachers are people that I left because it wasn't working out. And of those three, only one was truly horrible (as in, she criticized the music I wanted to play, said rude things about me all the time, suggested/insisted I do things that were not helpful or beneficial... Ranjit's "which teacher" indeed!!) The other two were perfectly good teachers but we just weren't a good fit.
Of the others, the reasons I didn't continue with them was either because they moved away, or I moved... A few of them I was very, very sad to no longer be able to work with them.
My current teacher is really great, we've been working together since Feb. He is a recent PhD graduate from a very highly regarded music school, which is why I put up with the horrible piano in the lesson room that's been assigned to us!