I don't let other people ride my bike and I sure as hell don't ride other peoples' bikes. I just don't want that responsibility.
I don't even like renting cars, but I'll do that occasionally. I simply don't like being responsible for somebody else's stuff.
I even get really nervous driving my wife's car without her in it...which is odd considering we both paid for it and I do ALL the maintenance and upkeep on it...but I would feel so horrible having to tell her that I crashed it...
You couldn't hear a dump truck driving through a nitro glycerin plant!
Badasses might screw with another badass. Nobody screws with a nut job.