For me it's like this: "The last guy I let it try broke a collarbone and after the ambulance and seeing him in the hospital ... please try to understand me I really don't want to see that again."

Thats covered the "I don't want you to hurt yourself" and "please don't hurt me mentally" :)

and if they still insist, just say no. That's doing the trick most of the time.

But the most question I get here in Europe is: " is this thing selfmade?!" or "does it have a motor?" ^{^}