I think I'm type O, but I've never donated blood. I probably would do it if they paid more, as it takes a while and would probably put me out for half the day. I'm rather selfish in a way, and I really believe that the best solution to a shortage like one for blood is to provide more incentive for people to donate. I also think people should get some tax rebate for being an organ donor and staying healthy enough to be viable. It's insane for hospitals to have such a massive organ shortage when so many people could donate, but never decide to. Or, people should be donors by default, but have the option to opt out if they really have some belief against it - amd opting out would make them ineligible to receive donations.