When I drive my car I like to know there's a brake as well as an accelerator. Of course, if there's just a brake I'll never get anywhere. But then I probably won't get anywhere if there's just an accelerator...

I'm not sure where the gears fit into this, but I think they do somewhere.

Concertina blue grass? I like the sound of that. Bagpipes too. But I've got a feeling most of the bluegrass enthusiasts I know might not. However any good irish session in my experience at some time will get round to playing something a bit grassy.