Paul810-
what about your wife, friends or present or coming children?
Of course, I teach every one I get the chance to. In fact, I've taught quite a few people to run heavy equipment as well.
I've always been heavily into vehicles and engines [thanks to my father, the shop mechanic], so I've always loved driving new things. I don't even own a boat or a motorcycle, but I got the endorsements just so I could if I ever wanted to.