I used to donate blood at my university. (Funnily enough, on blood donation days, part of the cafeteria was roped off to make room for those camp beds and all the medical stuff. Bleed where others eat, I'd say!)
But then I saw something on TV about one of the main blood donating organisations in my country. Apparently, some information on "how they get people to donate" leaked

to the media.
In a very cold, cynical way it was advised that people should be given the
feeling that they are helping others, although in reality they are financially supporting a major concern because most of the blood is turned into other products, which, unlike blood, are allowed to be sold. I was appalled and decided to not longer support a
concern with my own substance.
Waltraud