This 40% discussion reminds me of a discussion that I had during college.
I was interested in signing up to be in the bone marrow registry.
My friend said that he would never sign up, because if he were a match, he wouldn’t want to donate. His reasoning was that it simply would not be worth his time to do so, even if he were potentially saving the life of another person. He would have no problem to donating to someone he knew, but if it were an unknown person, forget it.
This conversation REALLY bothered me as I had known him for several years and never would have guessed… It really changed my view of him forever.