I've had some good instructors too but a few of them drive me batty. I pretty much go in just to have access to a bike in bad weather in a different environment with different tunes, and pretty much do my own thing when the instructions get crazy.

I really wouldn't mind getting certified and teaching part time. My equestrian trainer says I'm a really good teacher when I help her out with lessons. I'm sure I could figure out spinning. I've never seriously looked into what certification would entail, though.