I've been blessed with fantastic instructors but I have also been challenged by the instructor I replaced. When I took over the dojo I now run, the books were a mess, the dojo was dirty, the student base was down by half of what it had been and the dojo was in debt, and I spent most of this year getting students to be at the level they were supposed to have been for the belt they're wearing, while finding a way to make sure they stayed long enough to get fixed without getting discouraged about their previous subpar instruction. I also gave away some free training to students just to help that along.
The previous guy was about himself, not the dojo. And the dojo suffered because of it. Thankfully there were only a couple of students who ended up burning out. But it's sad, since the guy was a decent fighter and at one point was a decent instructor as well. If your business skills aren't up to par though and you don't make corrective action FAST, the stress WILL bleed into other areas, like it did here.