Blood type O negative is the universal donor blood type. People with blood type O negative can donate blood to people of all major blood types. Here are some things you might think or say: “I don’t need to prove myself.” “If it doesn’t feel right, I can’t do it.” “I can follow facts, but not people.” “I cannot listen to most people for too long.” “I am very picky when it comes to making friends.” “How people see me matters little compared to how I feel.” “Titles don’t impress me.” “I don’t give others a chance to disappoint me.”